Branch 10 commits behind

Hi, what does it mean when a branch on a repository on GitHub that I have forked says that I am 10 commits behind the original repository branch?

Thanks.

It means that the same branch on the original repository that you forked from has 10 commits that your fork does not have. In order to get those 10 commits into your fork, you’ll have to pull them down from the original repo and push them to your fork. You can find instructions on how to do this in our help documentation.

I hope that helps!

And how can I sync to the fork master?