Question regarding finishing the floor in my basement...

I intend to place the pad and carpet directly on the slab, but I assume I should
treat/seal it first. There will be some areas that will be tiled, so of course
I can only use a sealant there. Is drylok the recommended product? What
about laying down plastic?

I see drylok has a concrete sealant and a concrete floor paint...I am not sure
which is more appropriate for this.