me and quirby's collaborating process basically went like this:
one of us would send a early draft of the song for the other to work on for the day, then send it back to the one who sent it. it mainly consisted of adding the intro and outro, coming up with the lead melody and additional bassline, stuff like that. once finished, both of us agreed on the final product, one of us rendered it to .mp3 and .vgm and submitted it, listing one of us as collaborator.
the entire songwriting process itself was mainly kept within the song, as in that we basically sent our ideas within the project file and sought what the other thought of it before they worked on it. the cool thing about this was that me and quirby were kinda on the same page when going with this idea. the ideas she and i had meshed very well with each other and blended together to become what you hear in the track. it was a fun time, that's for sure.
but yea, by all means go for it! there are tons of people willing to collaborate on this site and tons of ways to collaborate in general...that, and it's just all around fun tbh. collaborating with someone can make memories, that's for sure ^^