Make a pull request (hereafter PR).
In the PR body, feel free to add an area label if appropriate by saying /area <AREA>.
The list of labels is here.
Also feel free to suggest a reviewer with /assign @theirname.
Once your reviewer is happy, they will say /lgtm which will apply the
lgtm label, and will apply the approved label if they are an
owner.
The approved label will also automatically be applied to PRs opened by an
OWNER. If neither you nor your reviewer is an owner, please /assign someone
who is.
Your PR will be automatically merged once it has the lgtm and approved
labels, does not have any do-not-merge/* labels, and all tests are passing.