Hmmm... I figured you already typed most of those in already.
Instructions are here: https://docs.nodebb.org/en/latest/upgrading/index.html.
If you've already pulled from the v1 repository just type (this will back up your database).
cd into your directory then:
If you didn't, I imagine the commands are (based on documentation above)
git fetch # Grab the latest code from the NodeBB Repository
git checkout v1.x.x
git merge origin/v1.x.x