How to use fitness coach in fifa 13 UT on ios (iPhone)?

I recently started playing fut mut I don't know how to use my fitness coach I got from a pack.

It works every time you use a fitness card. Say if you use fitness +40 on a player and a fitness coach has 10%, instead of giving that player just +40 fitness it will give them +44. This applies to all coaches and medics or whatever you call them.