Apply caulk to the back of the strip and stick it to each stud. Press it down until it’s flush with the wall surface. You can leave the wallboard off, but it’s best to put it back in place. Caulk along the seam to seal out air drafts and then reinstall the baseboard.
Mark each stud for notching using one of the nail guards as a template. Use a handsaw to cut the top and bottom lines for the notch to the depth of the plate thickness.
There will probably be several options for an electrical source to serve a new outlet. For instance, it is likely there are several suitable wall receptacles in any given room to extend the circuit to another room or another floor of the house.
A short piece of wire spliced to circuit wires and capped with a wire nut. Used for making connections to a terminal screw on a device such as a receptacle or to a grounding terminal inside an electrical box.