You see, to do a blitz you need your linebacker to come up to the line of scrimmage, acting as another defensive linemen in a way. Preferably, you have your linebacker come charging in right before the ball is hiked so that he has momentum to tackle the quarterback. However, in the case of blitzKRIEG, you need to be German, acting German in World War 2, and have a bunch of planes.

(SPOILER)Finding this a now overcompiled thread, I decided to have some fun. Please follow everyone else's advance and if you have further trouble, PM me.