Asking broadly like this is akin to asking for a guide on how to cook, it’s generally too broad for there to be a single guide. You first need to figure out what your goals are (you state one already, you’d like it to be externally accessible), determine what services you want to host, and then start looking at how to do so.
The advice I’d give is to start with a solid base, you’ll need something to self host on and it really shouldn’t be the PC you use for other things. Get it setup to run a virtualization OS such as proxmox and use that as your starting point. Then do a lot of reading. I spend probably three to four times as much time reading about the service I’m planning to deploy compared to actually doing the work to deploy it. Lastly, plan. You should have a solid plan in the beginning of how you want your service to work (what will be external vice internal only, how will you setup the networking stack to do that, are you going to have a domain, and will you use subdomains or folders to divide services, what does your IP space look like, will you host your own firewall to make the networking more controlled or fight with your ISPs router, do you want to use docker, kubernetes, or maybe full VMs for each service, do you want/need a UI to manage things from or are you comfortable with CLI, etc). These answers will lead you to guides for various services as well as service specific forums where help is more focused.
I would recommend prowlarr instead of jackett for indexer management, and pihole as at least an additional blocking service but in reality it’s really all you need for use at home. I’d also strongly encourage use of a VPN on your *arr download services. I use a separate box to run Plex and then have my *arrs all running on their own VM inside if it to provide separation and allow be to more easily segregate the network traffic (as someone that doesn’t really know docker that well it “just works” for me. Also probably worth looking at how to store your media on an external target, it’s easy to quickly accumulate 10s of TBs of media and trying to store that all on the server locally is asking for trouble. Better to set everything up on a NAS to start.