Another switch you may find in your home is a 4-way switch. These have four terminal screws and a fifth green one for a ground wire. Four-way switches are used between two 3-way switches to control lights from 3 or more locations. This can be handy if you have a large room with several entrances requiring light control from multiple locations.
The second most common type of switch found in residential buildings is a 3-way switch. These can be identified by three terminal screws and a forth, green screw for connecting a ground wire. A 3-way switch is used to control lights from two locations like at the top and bottom of a flight of stairs.
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.
Shut off the electricity at the service panel for the circuit you will be working on. Test the circuit using a known working lamp or other electrical device to be sure it’s off. Flip a light switch to be sure the bulb doesn’t light, or use a volt meter to test the wires and confirm the circuit is off. Remove the cover plate and the top and bottom screws holding the mounting strap to the outlet box. These are long screws and easier to remove with a drill-driver if you have one.