Slitherine

I'm a fairly new PC2 player, and I'm having a blast playing the Westwall DLC. I think I've cracked the code for playing the offensive missions successfully, but Arracourt is kicking my treadhead butt. So, I'm looking for advice. Not in terms of a full walk-through or anything, but more high-level guidance on how to conduct the defense, especially fulfilling the "Kill 20 vehicles" condition. And perhaps some pointers on force composition. Thanks!