You will likely get this through normal play, but if you'd like to get it quick, the first level you can do it on without spending more command points then you should, is 1-3. For this achievement you need to use at least one grenade, one rocket, and one airstrike. There are some rockets near where you spawn, and there are some grenades near mines up and to the left of where you spawn, or an enemy could drop some. The only ways to get airstirke is directly buying them or by buying the delta force agent. You cannot find them or get an enemy to drop them. Click the "C" in the upper left and buy one airstike for 18,000 command points. Once you have all three, use them by dragging them to a spot from their respective boxes on the right. (Don't kill yourself though! Use them away from where you are standing). The achievement should unlock when you use the last weapon.