Need Help Replacing Belts

Hello,

Both of the belts in my 93 Eagle Vision broke off and the engine was sizzling. Anyway, I bought two belts, and I've already replaced the belt that hooks up to the alternator it is the flat one with ridges.

However, I'm having problems replacing the other belt that is thin and looks like a gear, I think it hooks up to the air compressor. Is there a special technique for it, like the t-birds? The package reads:

Replaces Gates 7541
Replaces Dayco 15540
Replaces Goodyear 15545
Replaces Cadna 15540

Perhaps I got the wrong one? Can I drive around without it?

Thanks!

which engine do you have the 3.3 or 3.5?