Hosting is dead easy. Usually you just do sudo apt-get install apache2 for a start, and then it’ll host an html file on port 80 (HTTP), usually /var/www/html/index.html

w3schools.com is great for learning css and html.

You’d want to forward port 80 on your router then to get it accessible on the open web.

On your domain service, you’ll want to make an A record pointing to your IPV4 address and an AAAA record pointing to your IPV6 address.

If you have a dynamic IP (your IPV4 changes often) you can get scripts which run on a schedule to check your ip address and remotely update your A record using an API from your DNS.

You’ll also want to use certbot (an installable application) to manage an HTTPS certificate, then forward port 443 (HTTPS)

I know this is a very quick rundown, but hopefully it points you in the correct direction!