>Trying to get into contact with people to help with some of the work?
Don't ask people to waste time working with you if you've never made anything before and don't even know where to begin, not to mention when it's "just for you to learn".
>I already know which engine I want to use
>prioritizing which I should learn first
Make (or learn to make) a game prototype with your engine and ignore literally everything else. It's completely useless to make "character designs" and shit if you don't have anything resembling a game yet. Use MS paint placeholder graphics and some random audio files until you have the game's functionality down, then start polishing the assets.
Becoming a 1 man army is not a weekend project, it's going to take you something closer to half a decade if you want to go that way and not suck balls at it, unless you're specially talented. Art, music, and programming are all involved enough that most people to dedicate their lives to one of them. Of course you'll get overwhelmed and confused if you try to learn them all at once as a part of a game, those are 3 completely different fields so you need to treat them as 3 separate skills to learn, not as components of your game.
If you want to 1MA them then learn the required skills first, because any game you make now will not be relevant to you by the time you've learned art/music/whatever.
If you don't want to 1MA then you definitely need some kind of skeleton of a game before you can ask people to make assets for you, otherwise you're asking them to do work that is almost certainly never going to be used for anything.