Can not create new branches on issue forks 10.1.x branch

Encountered the same issue trying to work on #3156754

I reread this tons of times:

I recommend branching in your local checkout and pushing from there. That way you can update 10.1.x from the canonical drupal project, which you can keep at the origin Git remote. Then branch from there and push to the issue fork’s Git remote.

but I just don't understand what I should do, sorry...

Can you please write down a crystal clear step by step guide for dummies where nothing is given for granted?

I really would like to contribute to Drupal...

(I also think that this should be "officially" documented somewhere, in the issue forks guide maybe? Or, better, it would be nice to have a feature somewhere that easily allows to fetch updates from the issue fork itself)

@mxt

but I just don't understand what I should do, sorry...

One way to resolve it to follow below steps.

1. git checkout 10.1.x
2. git remote add drupal-123456
3. git checkout -b 123456-issue-short-description-10.x
4. Make changes
5. Commit changes
6. git push drupal-12356 123456-issue-short-description-10.x
7. Create MR from the UI or URL displayed in the terminal after push.

Thank you @Bhanu951,

I used DrupalPod → , and at the end I was able to create a new working branch based on 10.1.x in the (old) pre-existing issue fork following your suggestions.

In particular, using DrupalPod, I had to:

1. Start a DrupalPod session WITHOUT selecting an existing branch (so 10.1.x was automatically chosen)
2. Remove existing remote
3. Add new drupal-123456 remote
4. Create 123456-issue-short-description-10.1.x branch
5. Make/commit changes
6. Push the new branch
7. The new 123456-issue-short-description-10.1.x branch is now listed under the issue fork branches in the issue itself

Thank you.