Well, to start learning / using Linux, you'll need to learn how to read a lot. You can start here:
https://www.unix.com/where-do-i-download-linux-and-unix-/?s=
Also, compute responsibly! Learn about the network services you're running (and how to keep them secure or shut them off) BEFORE you attach the Linux box to the Internet - Cable modem users are a favorite target for would-be crackers.
Have fun, and be safe!