How to use Github personal access token for existing project using Visual Studio Code

Question

I'm working on a project and just saw the notice that Github stopped supporting password authentication on August 13. I've set up a personal access token. The official doc is about how to start from scratch: clone the repo then do the authentication. But I'm not sure how to use it for my existing project, especially how to set it up in VSCode, without losing my local changes. I've tried git remote set-url origin and git remote set-url origin --add but neither works. Thank you!