How to change branches and remote addresses?

Question

git

Good day! I really liked the editor and I want to move to it, but I want to ask some questions that I could not figure out myself, they will be in particular on git:
Here are the questions:
- When you click on Push, where does the request go, or rather to what address (if I have several) and which branch?
- When you click Fetch or Pull (Bottom right in the corner), where will the data go from, to be more precise, from which remote and from which branch?
- I have two remote addresses and I need to push not to origin, let's say, but to second_remote, moreover, I need to send not to the same branch where I am (for example, now I have a dev branch) but to the dev2 branch ( example: git push second_remote dev2). The same question is with pull, you need to spool, for example, not from origin/dev, but from origin/master.
Thanks in advance for your replies!
PS If you have any questions, ask in the comments, I will answer with pleasure)