A single pole light switch operates a single light or multiple lights from one location. A three-way switch operates a single light or multiple lights from two locations and connects to an additional three-way switch though a traveler wire. You can wire a three-way switch to operate as a single pole switch by not connecting any wiring to the traveler wire screw. You can reuse your old three-way switches as single poles without need to buy a new switch.
Turn off the electricity to the switch circuit by turning off the breaker at the main electrical panel.
Wire the three-way switch. Locate the two copper screws on the right side of the switch and a green ground screw near the switch bottom. An additional screw located on the left side of the three-way switch allows for the installation of the traveler wire between two three-way switches. This screw will not be utilized so as to allow the three-way switch to function as a single pole switch. Locate the two black wires inside the electrical switch box on the wall. Wrap one black wire each around each of the copper screws on the right side of the switch and tighten both screws. Find the bare copper wire inside the electrical switch box and wrap it around the green ground screw and tighten that screw also.
Install the light switch into the electrical switch box. Push all excess wiring into the electrical switch box and connect the switch to the top and bottom of the box with screws provided with the switch.
Cover the switch and electrical box with a switch cover plate using the two screws provided with the cover plate above and below the toggle.
Turn the electricity on to the circuit by turning on the breaker at the main electrical panel.