army_hq_lid this one is the flag the sandbags and the lid of the can
army_hq_tower_ps2 This one is the radio tower on hq
army_hq_pistons this is the pistons on the side of the super hq
army_hq_main this is the area where you would place the soda name and make a design
You should download the Rul3 map pack because it has all those files and you will be able to have an easier basis to work on them off of.