docs: Add more pages to the main docs.

Author: microbit-carlos

docs/api-docs.md

@@ -0,0 +1,11 @@
+---
+layout: default
+title: API Documentation
+nav_order: 3
+---
+
+# API Documentation
+
+The API documentation is generated independently of the rest of this docs and
+can be found here:
+https://microbit-foundation.github.io/microbit-universal-hex/api/

docs/contributing.md

@@ -1,7 +1,7 @@
 ---
 layout: page
 title: Contributing
-nav_order: 3
+nav_order: 5
 ---
 
 # Contributing
@@ -17,18 +17,33 @@ nav_order: 3
 
 ## How To Contribute
 
-WIP.
+Thanks for looking here! We'd love your help. The micro:bit project is only
+possible through contributions of companies and individuals around the world.
+
+This project is managed on GitHub, and the best way to contribute is to jump
+into the GitHub issue tracker to see what is available. Planned features are
+marked with the "enhancement" label, and know issues are marked with the "bug"
+label.
+
+https://github.com/microbit-foundation/microbit-universal-hex/issues
+
+If you're interested in working on any of these items, please respond to an
+existing issue, or file a new one, and mention @microbit-carlos.
 
 ## Code Of Conduct
 
 WIP.
 
 ## Bugs
 
-Issue tracker: https://github.com/microbit-foundation/microbit-fs/issues
+Please report any bugs in the GitHub issue tracker:
+https://github.com/microbit-foundation/microbit-universal-hex/issues
 
 ## Development Workflow
 
+This project follows a fairly standard node.js process:
+
 - `npm install` to install dependencies
 - `npm test` runs the complete test suite
-- `npm build` create a build with all the output formats
+- `npm build` creates a build of the library in all the output formats
+- `npm docs` builds the API documentation into the `docs/api/` directory

docs/index.md

@@ -10,7 +10,7 @@ nav_order: 1
 
 {: .fs-9 }
 
-<img alt="microbit-universal-hex logo" src="img/microbit-uh-logo.png" style="max-height: 100px; float: left; padding-right: 16px;">
+<img alt="microbit-universal-hex logo" src="img/microbit-uh-logo.png" style="max-height: 125px; float: left; padding-right: 16px;">
 
 Create Universal Hex files for the micro:bit.
 {: .fs-6 .fw-300 }

docs/uh-format.md

@@ -0,0 +1,15 @@
+---
+layout: default
+title: Universal Hex Format
+nav_order: 4
+---
+
+# Universal Hex Format
+
+The micro:bit Universal Hex format is a superset of the
+[Intel Hex file format](https://en.wikipedia.org/wiki/Intel_HEX) designed to be
+able to include data for multiple targets into a single file.
+
+This section of the docs is still a Work In Progress. For detailed information
+on the format please visit:
+https://github.com/microbit-foundation/spec-universal-hex