Take the the furniture out of the room. Spread out tarps on the floor at the base of the wall.
Spread primer over the whole wall with your paint roller, covering it completely. Let it dry for 12 hours.
Use your rubber trowel to spread drywall compound over about 4 square feet of the wall, starting at one end. Make it about ¼ inch thick.
Set the rubber trowel into the compound, flat, then pull straight out, to create texture peaks and in the compound.
Move the float over, next to the textured area, and repeat. Continue until you have pressed and pulled over the whole compound surface.
Spread on additional compound, next to the first section you did. Repeat, texturing the whole wall section by section. Let the compound set 24 hours. Move the furniture back in.