How do I USE XP-Boost

I have been looking for DAYS, probably 2-3 hours all totaled!!!  I have lots of XP Boost in my Battlepacks that I never used. There used to be a button on the lower right, next to the DEPLOY button or a part of it?  THAT does not show up any more!   I WANT to and need to use these XP Boost.  I have like 20 or more of them and I NEED the points!!!  THANKS, Animal