An error is displayed when pushing with git.

There are remote branches A, B, C.
When pushing from the local B branch to the remote C branch, it is rejected and the following error is displayed:

hint: Updates were rejected because a pushed branch tip is behind its remote
hint: counterpart. Check out this branch and integrate the remote changes
hint: (e.g. 'git pull ...') before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details.

It's been 3 weeks since I first used git, so I don't understand what this error means.

I would like you to point out your comments, including how to ask questions.