Cover the installation surface around the fireplace with a layer of felt paper and wire mesh. The felt paper acts as a moisture barrier for moisture wicking through the cement mortar, and the mesh holds the mortar in place. Cut the felt paper with a utility knife and staple it on the fireplace with the hammer tacker. Put wire mesh on top of the felt paper with the tacker as well, and cut it to fit with the metal shears.
Place at least one large bag of cement mortar mix into the wheelbarrow. If you are comfortable with the process you can do two bags at once. Add water according to the instructions on the bag and then mix the mortar with a shovel until you have a creamy cement mortar. Push the wheelbarrow close to your installation area so you can access the mortar.
Scoop some mortar out of the wheelbarrow with your trowel and push it into the wire mesh around the fireplace. Go up a couple of feet and cover the mesh with at least a half inch of cement mixture to give your stones a solid base. Scoop a half inch of mud onto the back of each piece of man-made stone with your trowel.
Start at the bottom of the wall so you can stack the stones on top of each other. Press the stones into the mortar mixture on top of the wire mesh. Work your way across the entire bottom row before you start the second row. You don’t need to grout the installation, so you can simply stack the stones tight and work your way up the fireplace until you are finished.