Snap an outline on the concrete floor to indicate where you will nail the sole plate with the powder-actuated nail gun. Lay the sole plate inside the layout line.
Place a powder cartridge into the nail gun's firing chamber. Place a drive pin headfirst into the barrel of the nail gun.
Grasp the handle of the powder-actuated nail gun and center the barrel tip 3 inches in from the butt end of the sole plate. Grasp the handle and hold the powder-actuated gun at a 90-degree angle from the sole plate so that the drive pin fires straight down into the sole plate and concrete floor.
Fire the nail gun, either by pulling the firing trigger or hitting the firing pin located at the top with a mallet. Pick the nail gun up to inspect the drive pin. Hit the drive pin's head with a hammer, if it's not fully impaled into the sole plate and concrete, until it is flush with the surface of the sole plate.
Move down the sole plate about 1 foot and repeat the nailing process. Stagger the drive pin location by moving it from one side of the sole plate to the opposite side each time to provide a secure hold without splitting the wood material.