How to activate Mirco-Transaction?

I bought a wep colour, how do I turn it on? the shop should have that somewhere.

EDIT: also can they be re-applied to other weps/alts?

EDIT2: I found the mirco transaction stash, but can it be re-applied?

EDIT3: I found everything by myself. GGG, pls put more info on how to get your buys

Yeah, there is a "Reclaim Effect" at the top right of the Microtransaction tab. Click it and the item with the effect you want to reclaim.