First follow the instructions in:
- Setting up a Gerrit repository
- You can say to import a git repo, but you can also create it empty.
After waiting for the repository to be created (it may take a few days), then you will have a git repo.
- You will need to add members to the project (coworkers). Ask in #wikimedia-releng irc
- If you want to import a repo from github, you will need to set the push permission to the repo group in Gerrit
- There is an admin UI to edit the permissions of the project, which generates a patch like https://gerrit.wikimedia.org/r/#/c/370652/ that you will have to self review and submit
- If you want to be able to submit patches manually on master after review until you set up Jenkins bot you will have to edit the permissions again to something like this https://gerrit.wikimedia.org/r/#/c/370772/