Here are some of the common git commands, or questions that I find myself googling a lot. Maybe they help you.

get a git repo

git clone

Show local AND remote branches

git branch -a

checkout and/or create your local branch

git checkout branch_name

checkout branch from the remote NOT just your local possibly new branch

git checkout origin/branch_name

basic flow to add changes to the current branch your working on

git add *
git commit -m "message"
git push

Using the * means all all your changes

update the repo to the most recent commits

git pull

delete remote branch after done your work on it

git push origin --delete branch_name

What is the difference between upstream and downstream?

“You’re downstream when you copy (clone, checkout, etc) from a repository. Information flowed downstream to you.
When you make changes, you usually want to send them back upstream so [your changes] make it into [the] repository […] that everyone [is] pulling from […] This is mostly a social issue of how everyone can coordinate their work rather than a technical requirement of source control. You want to get your changes into the main project so you’re not tracking divergent lines of development.” -Stackoverflow user

The point here is that, if you clone a repo, and start making changes on a local branch you’ve set up, you’re probably gonna wanna set the upstream remote as the git repo at some web address, and then send the work you’re doing to that upstream.