Improve readme & setup instructions

Author: ryan953

README.md

@@ -2,4 +2,35 @@
 
 Open the current file in the Phabricator/Diffusion web UI.
 
-Reads `~/.arcrc` by default for conduit credentials. Run `arc install-certificate` to get setup, or manually enter your conduit host/token information in the `Settings`.
+Just open a file, run the "Open In Diffusion: Open In Phabricator" command, & see file in your browser!
+
+The command looks like this:
+
+![searching for diffusion in the command palette](img/command_palette.png)
+
+## Reporting Bugs/Feature Requests
+
+Open an issue or pull request on [github](https://github.com/ryan953/atom-open-in-diffusion/issues).
+
+## Setup
+
+This plugin tries to read `~/.arcrc` by default for conduit credentials, falling through manually set settings in atom.
+
+#### Option 1: Setup `arc`
+
+1. Follow the [Installing Arcanist](https://secure.phabricator.com/book/phabricator/article/arcanist/#installing-arcanist) steps to setup the `arc` command on your computer.
+2. Run `arc install-certificate` in your terminal.
+
+If you can run `arc diff` from your computer then open-in-diffusion will work.
+
+#### Option 2: Atom Settings
+
+Enter your conduit host/token information in the plugin settings:
+  ![](img/atom-settings.png)
+
+
+1. The Condiut API endpoint is the domain where phabricator is installed with the `/api/` path.
+2. Then, you can visit the `/setttings` page to get your api token.
+  - Click the "Generate Token" button in the top-right.
+
+    ![](img/phab-settings-tokens.png)