Welcome! If you go to Derek’s or Jack’s or mine or anyone’s page you can click on Relays to see the ones they use and start out with the same ones. 
Some are free and some are paid. We like supporting relay runners as it costs them to host relays.
Over time you will learn more and might choose other relays as well.
Recommended is between about 6-12 or so, tho some people have more.