Replying to Someone explain how a fucking roof rack works?

my car doesnt have any kind of built-in mounting stuff on the top like some SUVs... I wana buy the Thule 726 flat-top  rack but i cant figure out everything I need to get to have it ready 2 mount. Starting to piss me off... no clear explanation online. is there just clamps that hook to the side of the roof, or do I need to buy a whole nother bar system and then mount the thule on that? Btw its a 99 jetta gls if that helps, I just want to order everything online at once and not deal with all this bullshit "add seperate clamps and this and ahtat