It kind of flooded my screen with pictures of skins and things and didn't explain how it worked.
Clicking on something gave me the option of buying two things the pass or the pass bundle, i still had the CP they gave me at the start so i used that on the pass and received... nothing?
Now i'm very very very slowly leveling up the pass (i assume), but wasn't i doing that anyway? What did buying the pass do?
Did i waste my CP?

Without buying the battle pass you would only be unlocking the items labeled Free. You would still see your progression through it as an incentive.