A few things I had to figure out:

1. Pulling any changes to a repository that you forked from:

From this answer on stackoverflow:

• Add the remote, call it "upstream":

  git remote add upstream https://github.com/whoever/whatever.git

• Fetch all the branches of that remote into remote-tracking branches, such as upstream/main or upstream/master:

  git fetch upstream

• Make sure that you're on your main branch:

  git checkout main

• Rewrite your main branch so that any commits of yours that aren't already in upstream/main are replayed on top of that other branch:

  git rebase upstream/main

Note: the update is local, after this you'll have to push to the forked repository on github.

2. Permanently delete commits from repository:

From here:

• First, check out the commit you wish to go back to (get sha-1[commit ID] from git log) git reset --hard 9d3c3a0caa7f7b35ef15adb96fc80fcbb59ac72a

• Then do a forced update. git push origin +9d3c3a0caa7f7b35ef15adb96fc80fcbb59ac72a^:develop

• Push specific commit git push origin 9d3c3a0caa7f7b35ef15adb96fc80fcbb59ac72a:develop

Check out a much lazier .txt version of this document here