Do we have some syncing overview?

Is there some document describing how syncing to ecloud works?

I have an own Nextcloud server i would like to use instead or in parallel to my account for syncing, because i have there plenty of space, file versioning, and a bunch of for me useful apps like PhoneTrack, Mindmap…

Thinking of i installing the Nextcloud client on my phone so i get control, but how to make it sync everything that /e/ would normally sync - and then possibly not syncing some things (i.e i often have large temporary downloads)