I have a friend who's asked me to teach him a bit about Linux and computers in general when we hang out. We haven't done much, basically I let him muck around i

I have a friend who's asked me to teach him a bit about Linux and computers in general when we hang out. We haven't done much, basically I let him muck around in a TTY for a bit one day. I've considered just giving him one of my old spare PCs and having him build his own Gentoo system. Any tips for following this approach?