Contribution page

CONTRIBUTING.md

@@ -1,3 +1,113 @@
 # Contributing guide
 
-Page in construction, for now go to https://github.com/pymc-devs/pymc-experimental#questions.
+Thank you for your interest in contributing to PyMC and PyMC-experimental!
+
+This page outlines the steps to follow if you wish to contribute to the pymc-experimental repo and clone the repo locally.
+
+## Install locally
+**1**: Create a folder `pymc-devs` in your local machine and follow the steps on [cloning PyMC locally](https://www.pymc.io/projects/docs/en/latest/contributing/pr_tutorial.html).
+
+Since PyMC-experimental should integrate with the latest version of PyMC, it is recommended that any development work on PyMC-experimental must also work with the latest version of PyMC.
+
+You should now have a local copy of PyMC under `pymc-devs/pymc`.
+
+**2**: Fork the PyMC-experimental repo and clone it locally:
+
+```
+git clone [email protected]:<your GitHub handle>/pymc-experimental.git
+cd pymc-experimental
+git remote add upstream [email protected]:pymc-devs/pymc-experimental.git
+```
+
+You should now have a local copy of PyMC-experimental under `pymc-devs/pymc-experimental`.
+
+Create a new conda environment by first installing the dependencies in the main PyMC repo:
+```
+conda env create -n pymc-experimental -f /path/to/pymc-devs/pymc/conda-envs/environment-dev.yml
+conda activate pymc-experimental
+pip install -e /path/to/pymc-devs/pymc
+
+# ignores the specific pymc version to install pymc-experimental
+pip install -e /path/to/pymc-devs/pymc-experimental --ignore-installed pymc
+```
+
+**3** Check origin and upstream is correct.
+
+**PyMC**
+```
+cd /path/to/pymc-devs/pymc
+git remote -v
+```
+Output:
+```
+origin  [email protected]:<your GitHub handle>/pymc.git (fetch)
+origin  [email protected]:<your GitHub handle>/pymc.git (push)
+upstream        [email protected]:pymc-devs/pymc.git (fetch)
+upstream        [email protected]:pymc-devs/pymc.git (push)
+```
+
+**PyMC-experimental**
+```
+cd /path/to/pymc-devs/pymc-experimental
+git remote -v
+```
+Output:
+```
+origin  [email protected]:<your GitHub handle>/pymc-experimental.git (fetch)
+origin  [email protected]:<your GitHub handle>/pymc-experimental.git (push)
+upstream        [email protected]:pymc-devs/pymc-experimental.git (fetch)
+upstream        [email protected]:pymc-devs/pymc-experimental.git (push)
+```
+
+
+
+## Git integration [(from PyMC's main page)](https://www.pymc.io/projects/docs/en/latest/contributing/pr_tutorial.html)
+
+**1** Develop the feature on your feature branch:
+```
+git checkout -b my-exp-feature
+```
+
+**2** Before committing, run pre-commit checks:
+```
+pip install pre-commit
+pre-commit run --all      # 👈 to run it manually
+pre-commit install        # 👈 to run it automatically before each commit
+```
+
+**3** Add changed files using git add and then git commit files:
+```
+git add modified_files
+git commit
+```
+to record your changes locally.
+
+**4** After committing, it is a good idea to sync with the base repository in case there have been any changes:
+```
+# pymc
+cd /path/to/pymc-devs/pymc
+git fetch upstream
+git rebase upstream/main
+
+# (pymc-dev team) Please double check this
+pip install -e /path/to/pymc-devs/pymc
+
+# pymc-exp
+cd /path/to/pymc-devs/pymc-experimental
+git fetch upstream
+git rebase upstream/main
+```
+Then push the changes to the fork in your GitHub account with:
+```
+git push -u origin my-exp-feature
+```
+
+**5** Go to the GitHub web page of your fork of the PyMC repo. Click the ‘Pull request’ button to send your changes to the project’s maintainers for review. This will send a notification to the committers.
+
+## Final steps
+
+Review contributing guide in [PyMC's main page](https://www.pymc.io/projects/docs/en/latest/contributing/index.html).
+
+FAQ [page](https://github.com/pymc-devs/pymc-experimental#questions).
+
+Discussions [page](https://github.com/pymc-devs/pymc-experimental/discussions/5).