Install Git LFS just in case.
git lfs install
Using Unity version 2021.3.17f1 LTS
Git clone the repo and open with Unity (all the dependencies should be installed automatically by Unity.
How to branch and push to remote:
git checkout -b <name>
git add .
git commit -m "<message>"
git push -u origin <name>
How to fast forward back to main on your branch (note: this will override your remote and local branch):
git checkout main
git branch -D <name>
git checkout -b <name>
git push -u origin <name>