I don't plan on deleting my reddit accounts to be honest, I put way too much work in them, plus they have some saved posts that I really need and use as a reference from time to time. Also, there are some communities there that I don't believe will shift over here (for some, I am sure they won't, since they're other not that big amd moderation is not a problem for them), so I'll mostly be using Lemmy and Reddit interchangeably.
My main use of Reddit was discussing movies and series that no one in my immediate circle were interested in. So far, I'm not seeing much content in that area (edit: on Lemmy), but maybe we can create the communities ourselves?
I don't know how to do it from the Jerboa app, only through the web UI. Login on your Lemmy instance, top right corner, the hamburger button --> Create Community.