Self Install XM Tuner?

I saw Sirius/XM was running a special for 3 months of free radio and I have a 2008 Prius touring with JBL audio which I thought it was already equipped with satellite but nothing happened when I hit the AM•SAT button. So I went out and bought a satellite tuner but I haven’t found any intuitive installation instructions online (even checked old threads on here on PC). Has anyone here ever self-installed an XM tuner in their car?