Select it by using the up or down directional buttons then run to a place you want to set it and press L1. Run a good distance away and while holding down L1 to prep the charge, press R1 to detonate the explosive. Very useful in crowds and boss fights.
Stupidity isn't a virus, but it sure is spreading like one!
tap L1+R1 together and you snap toward your nearest enemy and stun shot them. also, if you ever go down by a zombie, if you hit R1 as soon asyou hit the groundyou shoot them off. Thus, eliminating the "qte" dilemma with that lol