I used browse.feddit.de to get my first communities and have just added to them a little at a time as new ones of interest cross the "all" feed or like recently i installed NixOS and wanted to see if there was a community for it and there was. So i started out with maybe 10-15 core subs and have branched into quite a few more. I also run !t_mobile@lemmy.ml because i liked the news and discussion on /r/tmobile. The lemmy community doesnt get much discussion, but it gets some and i add what interests me. Others are free to contribute as well.