The first step is to get on the Tor network. Better check with the ISP that does not violate terms of service. You can set up the Tor instance as an entry, intermediate, or exit node. The last may open you up to legal liability, since if someone goes thru your exit node for an attack, it will be traced back to the exit node. So better mebbe to set up as entry or bridge node.
Once you are on theTor network, onion addresses are easy. But first you need to be on Tor.
sidd