How do you structure deals with co-founders?

I'm a developer and drummer, building a drum training application (in-depth lessons, logging/tracking, custom auto-generated practice session playlists, facilitating paid tuition and courses between student and teachers). A lot has already been done, but to bring to life the full scope of what I'm imagining, I foresee a huge amount of work to be done in areas that either aren't my strength or would take too much time for me to do well alongside the work I'm already doing.

I have capital to outsource some amount of that work, such as social media management, ad spend, etc. but not currently enough to hire the talent to help manage and develop the business and the software it's based on.

I often think about how it might look to take on a co-founder or two, but I really have no idea how those kinds of arrangements are structured. How would you manage this remotely (or not)? What's involved legally? How do deals look? How do you cut the pie? How do you formally divide obligations and manage expectations? How do you manage ownership of intellectual property? How do you handle things if the co-founder relationship doesn't work out?

Any suggestions where to read case studies specifically about these kinds of questions? Or have answers of your own, would love to hear them. Cheers.