Think of this like any specialty skill. It’s hard the first time but will quickly become second nature. But first you have some homework…

If you have a way to section off your network and understand how to expose service’s to the web you are off to a great start from the networking side.

For the ssl cert. As others have mentioned it’s time to go read up on how DNS works. You don’t need to go super technical (yet, if ever) - but getting you head around DNS delegation and registers will answer all the questions you have here. The super TLDR is you “buy” a domain and tell your register where they can tell others to find the records for that domain. Once you can prove you own the domain you can get certs. There are a bunch of options going this path, I’m most familiar with the enterprise grade choices (aka super expensive) so am not the best to recommend something for someone starting out.

Now for VMs. I’m sorry to say it’s homework time. You have three primary choices: everything in a full VM, everything in containers or a mix. If your interested in having a GUI (learn the cli when your comfortable) then I’m going to recommend you look at two different technologies: proxmox (it’s overkill but might be what you want) or virt-manager.