Coach Nana explains the basics of defensive fronts, focusing on what the numbers in calls like a "4-3," "4-4," or "4-2" represent. The first number in a front call indicates the number of D-linemen, and the second number indicates the number of linebackers. For instance, in a 4-3 defense, there are four D-linemen (two tackles and two defensive ends) and three linebackers, which could include a middle linebacker, a Sam linebacker, and a Will linebacker. In a 4-4 defense, you would have four linebackers, likely two middle linebackers with outside linebackers pushed to the outside. In a 4-2 defense, there would be two middle linebackers, possibly lining up in free gaps, along with a nickel and two safeties.