Could anyone help me with just how to check the trans fluid or replace the drive belt in a 99 olds cutlass?

Umm... there were no Olds cutlasses in 99. GM stopped making them in 97.
Do you perhaps have an Alero, Intrigue, or Aurora?
Trans fluid should be the stick with the red handle near the back of the engine (towards windshield) on the right side. For the drive belt, you should get a Haynes manual.