chore: add instruction in CONTRIBUTING.md

Author: katelynsills

CONTRIBUTING.md

@@ -1,28 +1,47 @@
-## Current intention
-
-The current work aims at creating a progressive learning experience into writing Smart Contracts as proposed by Agoric. An attention is given to provide a very simple first experience and increase the complexity gradually
-
-Identified sources of complexity:
-- How contracts can be expressed
-    - Jessie
-- What can be expressed in contracts
-    - multi-party contracts with invites
-    - turn-based contracts
-    - ERTP framework
-        - ContractHost
-        - Escrow
-    - CoveredCall
-    - hierarchical rights
-    - non-determinism (time, randomness)?
-- Infrastructure/Tooling
-    - @agoric npm packages
-    - User interface
-    - Vats
-    - Swingset
-    - Cosmic-Swingset
-
-
-### Progress
-
-Progress can be followed [on this
-board](https://github.com/Agoric/documentation/projects/1?fullscreen=true)
+## Build Locally
+
+To run a local server to see the changes in real time, run:
+
+```shell
+npm run docs:dev
+```
+
+Note that changes to the site config may require stopping this program
+and restarting.
+
+To build the site as it will be built for production, run:
+
+```shell
+npm run docs:build
+```
+
+## Github Actions and Continuous Integration
+
+On every pull request and on every commit to master, the following
+Github Actions run:
+
+* Test the build - tests that a build does not error and that the
+  result passes html5 validation
+* Spellcheck - checks against a dictionary and a local wordlist
+
+## Spellcheck
+
+This is currently only available in Github Actions on Pull Requests.
+Any words that do not pass spell check will be shown in the logs of
+the Github Action. Please either fix the words or add them to the list
+in `.wordlist.txt`. 
+
+![](./contributing-assets/spellcheck-results.png)
+
+## Check Links
+
+This is not yet hooked up to continuous integration, but to check the
+internal Vuepress links locally (this does not test external links or
+router-links), run:
+
+```shell
+npm run check-links
+```
+
+Links should be relative and in [this format](https://vuepressbook.com/tutorial/tutorial2.html#linking-to-headers-inside-a-file).
+