git commands for contributing in Flask

[Yourun-proger]

I do not know if it is possible to ask this type of question here, but I hope that it is possible and that they will help me.
I wanted to contribute to the flask a second time, but wondered about the git.
I have local branches like this:

• fix (my first contribution branch)
• main

now I'm in the fix branch
I would like to make a new branch, but what is the correct way to do it?
So:

git checkout main
git checkout -b my-branch-name origin/2.0.x

or like this:

git checkout main
git fetch origin
git checkout -b my-branch-name origin/2.0.x

Or something else? Sorry for the possibly stupid question. I just don't want to mess up my fork and local repo.
I've read the resources for these commands, but I'm not sure how to do...

[greyli]

The contributing guide contains everything you need to know to contribute to Flask.

[Yourun-proger]

Thank you so much!