add contributing section

README.md

@@ -75,7 +75,78 @@ The following scripts are made available via [package.json](./package.json):
 
 ## Contributing
 
-Contributions are welcome! Please feel free to submit a Pull Request.
+### Reporting an Issue
+
+Issues for ArchivesSpace's technical documentation are [tracked in Jira.](https://archivesspace.atlassian.net/jira/software/projects/TD/boards/57) If there isn't a ticket in this system,  go ahead and make one. Be
+sure to include a **title and clear description** with as much relevant
+information as possible.
+
+### Creating a Pull Request
+
+#### Fork & create a branch
+
+When you are ready to start working on an issue, please assign it to yourself
+as an indication that you are working on it. Then [fork ArchivesSpace][] and
+create a branch with a descriptive name.
+
+A good branch name would include the ticket number in it. For example, if you
+are working on JIRA ticket TD-123:
+
+```sh
+git checkout -b TD-123-descriptive-short-title
+```
+
+#### Get the test suite running
+
+Before running any tests, you will need to set up your environment. See [Running TechDocs locally](#running-techdocs-locally).
+
+#### Implement your fix, enhancement or new feature
+
+At this point, you're ready to make your changes! Feel free to ask for help;
+remember everyone is a beginner at first
+
+* ArchivesSpace Program Team - ArchivesSpaceHome@lyrasis.org
+
+#### Make a Pull Request
+
+At this point, you should switch back to your main branch and make sure it's
+up to date with ArchivesSpace's main branch:
+
+```sh
+git remote add upstream git@github.com:archivesspace/tech-docs.git
+git checkout main
+git pull upstream main
+```
+
+Then update your feature branch from your local copy of main, and push it!
+
+```sh
+git checkout TD-123-descriptive-short-title
+git rebase main
+git push --set-upstream origin TD-123-descriptive-short-title
+```
+
+Finally, go to GitHub and [make a Pull Request][https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/creating-a-pull-request] :D
+
+TravisCI will run all test suites against the pushed branch. We care about
+quality, so your Pull Request won't be merged until all test suites pass.
+
+##### What happens after you submit a Pull Request?
+
+All Pull Requests are reviewed by at least one member of the ArchivesSpace [Core Committer's Group](https://archivesspace.atlassian.net/wiki/spaces/ADC/pages/102893918/Core+Committers+Group).
+
+A core committer reviews the issue/ticket associated with the Pull Request to make
+sure they understand what the code changes are supposed to do. Next, they review
+the code changes to see the proposed solution. Then they checkout the branch to
+test the solution in a running instance of ArchivesSpace.
+
+During the review, the core committer may have comments or ask questions in the
+Pull Request. Once the comment/questions have been answered/resolved, a Pull
+Request can only be accepted and merged into the core code base by a core
+committer if:
+
+* All test suites are passing.
+* It is up-to-date with current main.
 
 ## 📖 Additional Resources