docs: update schema validation and index sections

- Refined instructions for applying and testing schema (users/authors)
- Adjusted advanced exercise for authors with TODO methods
- Improved validate sections and log explanations
- Updated index checking instructions (mongosh / VS Code)
- General wording and pattern consistency fixes across docs

Author: ricardohsmello

docs/60-schema-validation/2-validate-users.mdx

@@ -93,7 +93,7 @@ The function uses the `db.command()` method to apply the schema to the `users` c
 <TabItem value="java" label="☕️ Java Spring Boot">
 In this step, we’ll review the code that applies schema validation to the users collection.
 It’s already implemented in `SchemaValidationConfig.java` no changes needed. We’ll look at two methods:
-```java title='infrastructure/config/SchemaValidationConfig'
+```java title='src/main/java/com/mongodb/devrel/library/infrastructure/config/SchemaValidationConfig.java'
 @Configuration
 public class SchemaValidationConfig {
 

docs/60-schema-validation/3-validate-authors.mdx

@@ -24,7 +24,7 @@ This is an advanced exercise that requires you to write code. If you get stuck a
 <TabItem value="java" label="☕️ Java Spring Boot">
 In this advanced exercise, you will extend the [SchemaValidationConfig](https://github.com/mongodb-developer/library-management-system/blob/java-server/java-server/src/main/java/com/mongodb/devrel/library/infrastructure/config/SchemaValidationConfig.java) class to support the authors collection.
 Two methods are already defined in the class, but both are left with `// TODO` markers for you to implement:
-```java title='../infrastructure/config/SchemaValidationConfig'
+```java title='src/main/java/com/mongodb/devrel/library/infrastructure/config/SchemaValidationConfig.java'
 private void applyAuthorSchema(MongoDatabase db) {
     // TODO: Implement the schema for authors ($jsonSchema with required 'name', 'bio', etc.)
 }

docs/70-indexing/1-create-compound-index.mdx

@@ -8,7 +8,6 @@ In this exercise, you will build a compound index following the ESR rule, compar
 
 ## Explore the code
 
-
 <Tabs groupId="server">
 <TabItem value="node" label="🚀 NodeJS/Express">
 
@@ -82,17 +81,18 @@ In this exercise, you will build a compound index following the ESR rule, compar
 
 <TabItem value="java" label="☕️ Java Spring Boot">
 
-1. Let’s start with our [`java-server/src/main/java/com/mongodb/devrel/library/domain/model/IssueDetail.java`](https://github.com/mongodb-developer/library-management-system/blob/java-server/java-server/src/main/java/com/mongodb/devrel/library/domain/model/IssueDetail.java) record. Right now, it looks like this:
-    ```
+1. Let’s start with our [`IssueDetail`](https://github.com/mongodb-developer/library-management-system/blob/java-server/java-server/src/main/java/com/mongodb/devrel/library/domain/model/IssueDetail.java) record. Right now, it looks like this:
+    ```java title='src/main/java/com/mongodb/devrel/library/domain/model/IssueDetail.java'
     @Document(collection = "issueDetails")
     public record IssueDetail(
         // fields ..
     ) {}
     ``` 
 
-2. Now let’s optimize queries that need to filter or sort by multiple fields. For example, we often query by user._id, returnedDate, and borrowDate together.
+2. Now let’s optimize queries that need to filter or sort by multiple fields.
+    For example, we often query by `user._id`, `returnedDate`, and `borrowDate` together.
     To speed this up, we can add a compound index using the **@CompoundIndex** annotation.  
-    ```java  
+   ```java title='src/main/java/com/mongodb/devrel/library/domain/model/IssueDetail.java' 
     @Document(collection = "issueDetails")
     @CompoundIndex(
             name = "user_returned_borrow_idx", 
@@ -110,7 +110,7 @@ In this exercise, you will build a compound index following the ESR rule, compar
 3. Open the `application.yml` and include the property `auto-index-creation: true`. At the end, your configuration will look like this:
 
 
-    ```yaml
+    ```yaml title='src/main/resources/application.yml'
     spring:
       data:
         mongodb:
@@ -119,11 +119,11 @@ In this exercise, you will build a compound index following the ESR rule, compar
           auto-index-creation: true
     ```
 
-This ensures that any indexes defined in your domain models (for example with @Indexed) will be created automatically by Spring Data MongoDB at startup.
+This ensures that any indexes defined in your domain models (for example, with `@Indexed`) will be created automatically by Spring Data MongoDB at startup.
 
 1. Stop the running app.
     1. Locate the bottom panel and click on the `TERMINAL` tab.
-    1. Press Ctrl+C to interrup the running app
+    1. Press Ctrl+C/Cmd+c to interrupt the running app
 
 1. Restart the app typing in the Terminal:
 
@@ -132,15 +132,21 @@ This ensures that any indexes defined in your domain models (for example with @I
     ```
 As soon as the application starts, you will see log entries showing the creation of indexes, similar to the image below.
 
-<Screenshot url="https://github.com/mongodb-developer/library-management-system" src="img/screenshots/70-indexing/index-creation.png" alt="Spring Index creation" />
+<Screenshot url="https://github.com/mongodb-developer/library-management-system" src="img/screenshots/70-indexing/1-index-creation.png" alt="Spring Index creation" />
 
-To double-check, you can either open **MongoDB Compass** and inspect the Indexes tab of the issueDetails collection,
-or run the following command in mongosh:
+To double-check that the index was created, you can run the following command in mongosh:
 
 ```
 db.issueDetails.getIndexes()
 ```
 
+:::info
+Optional: If you’re using the MongoDB for VS Code extension
+, you can also open the issueDetails collection in the VS Code sidebar and inspect the Indexes tab directly.
+:::
+
+<Screenshot url="https://github.com/mongodb-developer/library-management-system" src="img/screenshots/70-indexing/2-index-vscode.png" alt="VS Code Playground" />
+
 </TabItem>
 </Tabs>
 

docs/75-optimize/2-patterns.mdx

@@ -77,7 +77,7 @@ At this point, we also have to do additional queries to display the first five r
 Let's look at the current code that is used to retrieve a single book.
 Open the [`BookService`](https://github.com/mongodb-developer/library-management-system/blob/java-server/java-server/src/main/java/com/mongodb/devrel/library/domain/service/BookService.java) class and check the `getBook` method:
 
-```java
+```java title='src/main/java/com/mongodb/devrel/library/domain/service/BookService.java'
  public Optional<Book> getBook(String id) {
         Aggregation aggregation = Aggregation.newAggregation(
                 Aggregation.match(Criteria.where("_id").is(id)),
@@ -106,9 +106,9 @@ Open the [`BookService`](https://github.com/mongodb-developer/library-management
 
 ```
 
-This method is doing the same steps as the Node.js code:
+The method does the following:
 
-1. **Aggregation.match**: filters the book by _id (just like a SQL WHERE).
+1. **Aggregation.match**: filters the book by `_id` (just like a `SQL WHERE`).
 
 2. **LookupOperation.newLookup()**: performs a join with the issueDetails collection to get related records.
     - Here we filter only reservations or borrowed books that haven’t been returned yet.
@@ -117,7 +117,7 @@ This method is doing the same steps as the Node.js code:
 3. **Aggregation.addFields()**: computes the available field by subtracting issued books from the total inventory.
 4. **Aggregation.project()**: removes the temporary details field before returning the final result.
 
-Just like in Node.js, this approach works but it’s not efficient — it simulates a relational-style query in MongoDB.
+This approach works, but it’s not efficient — it simulates a relational-style query in MongoDB.
 We will later see how to apply patterns to improve this.
 </TabItem>
 </Tabs>

docs/75-optimize/3-optimize.mdx

@@ -34,13 +34,17 @@ How many calls do you need to do to your database now? Do you still need an aggr
 </TabItem>
 
 <TabItem value="java" label="☕️ Java Spring Boot">
-Open the BookService class, and look for the getBook method. How could you simplify this code to make it blazing fast, using the patterns we just discussed?
+1. Open the `BookService` class
+
+2. locate the `getBook` method.
+
+How could you simplify this code to make it blazing fast, using the patterns we just discussed?
 
 <details>
   <summary>Click here to see the answer</summary>
 
 <div>
-```java
+```java title='src/main/java/com/mongodb/devrel/library/domain/service/BookService.java'
   public Optional<Book> getBook(String id) {
     return bookRepository.findById(id);
   }