Don't worry, full release will feature a fully fledged tutorial with everything a newcomer, or even a veteran, needs to know about the game and how to play it. It's just something that's being worked on for the final product, so you might have to rely on tooltips, other players, and your intuition to get things going on your end.
Also, about boy groups: the devs currently have no intention of adding those, since after the game's officially released for PC, they'll still have a lot of work ahead of them with the Switch port. Maybe after that they might think about DLCs and expansions, but there's always a possibility that modders will be able to implement the possibility of having boy groups.