Load a strip of 8d framing nails into the nail gun. Align the joist at the desired position on the wall plate. Position the nail gun's tip roughly 7/8 above the wall plate -- this is the point of entry for the nail. If you're using longer nails, such as 16d nails, drive the nail through the joist at a height equal to roughly one-third the length of the nail.
Move the gun's tip 1 1/8 inches from the edge of the wall plate. Press the gun's tip against the face of the joist. Tilt the gun to a 30-degree angle -- 30 degrees is slightly lower than halfway between the wall plate and the top edge of the joist. Pull the gun's trigger to drive the nail through the joist and into the wall plate.
Position the gun roughly 1 1/8 inches from the opposite edge of the same side of the joist. Elevate the gun approximately 7/8 inches above the plate's top face. Press the gun's tip against the joist's face and tilt the gun to a 30-degree angle. Pull the trigger to drive a nail through the joist and into the plate.
Move to the opposite side of the joist. Drive a nail through the center of the opposite side of the joist at the same height and angle as the previous nails. Apply the same nailing pattern and toe-nailing technique to the remaining joists.