Don't have a good guide, but in addition on the thing you plan to selfhost yourself you need to decide where it's supposed to run. In a rented VM from a hoster? There are several ones where you can get a decent VM for a few bucks each month.
Nowadays, Docker (or containers in general) are very popular, as an alternative to directly installing services on the vm. They make many things easier, but it's another thing to learn about when you're just starting - fortunately, there's plenty of guides etc!
Cool! Home Assistant has it and I can imagine Nextcloud as well but those are overkill just for that.