Add more words to contributing guide

CONTRIBUTING.md

@@ -4,6 +4,10 @@ This is living document describing how to contribute to SeqViz.
 
 ## Development
 
+The sections below describe setting up the development environment and opening a PR against the `develop` branch.
+
+### Setup
+
 Before making or PR'ing changes, please set up and experiment with the demo application. Steps for doing that are described below.
 
 Install `seqviz` packages in the repository and repository's demo directories:
@@ -20,3 +24,9 @@ Start the demo application:
 ```bash
 npm run start
 ```
+
+Visit the demo application at [http://localhost:3010](http://localhost:3010) and experiment with sequence selection, clicking annotations, rotating the circular viewer, etc. As much as possible, try to validate that your change does not break existing functionality. The testing of `seqviz` is sparse; we rely on the demo application to catch regressions.
+
+### PR
+
+After making a change, open a PR against the `develop` branch and get it approved and merged by someone who works at Lattice Automation or [@jjti](https://github.com/jjti). They will merge it and cut a release.