Stock up on a gun of your choice and lots of ammo to make this mission easier. Head out to the location of the marker and you will meet 3 soldiers situated in the fields.
Approach them first, then go to the northern house located nearby. Here you need to rescue some survivors before they are ripped into shreds. Whip out your gun then shoot away. The shotgun works best here since it's close quarters combat and the zombies are cramped up together. Sometimes though, a Juggernaut will enter the mission which makes it a lot tougher. Just continue blasting away to it's head since shooting is safe for the survivors unlike grenades and molotovs which will damage them with the splash coverage.
Afterwards you will acquire a new command for your Radio Assistance Menu.