Here are some ideas:
- Often the company where you bought the domain will also offer email and website hosting. That would be the simplest way to start using the new domain. Otherwise, find a company that provides those two services together.
- Create a file called index.html with the text "hi!". Depending on the web host, it may be possible to do that with a web interface. Otherwise, learn how to edit files on your site using FTP, file transfer protocol.
- Learn HTML and CSS by playing around with that one file. If you find that you enjoy it, well, you'll never stop learning - and who knows where the road might go!