New Clutch slave cylinder not working

Be careful “just driving it”. A clutch slipping, even just a little, is wearing it MUCH faster than one that isn’t slipping. Maybe you’re lucky and the clutch itself is fine and it’s just all the problems with your hydraulics that are causing the problem, but that won’t be the case long if you driving it with it slipping.

I know you just got it, and you really want to drive it, but park it until it’s fixed right and it will cost you a whole lot less in the long run.