A motion sensor activates itself when movement is detected in front of its sensor. To connect two lights to a single motion detector -- in effect creating two motion detector lights without the costs involved -- wire the motion detector to both lights. The procedure is straightforward, requires a few household tools and does not need any electrical skills.
Decide on the lighting fixture that will be supplying electrical power to the motion detector and two security lights -- the fixture could be over the garage door, on a porch or some other exterior wall of the house. Cut the power to the lighting fixture by pulling the appropriate fuse/tripping the appropriate circuit breaker at the fuse box.
Unscrew the bulb or bulbs from the lighting fixture. Place the bulbs aside. Remove the screws from around the lighting fixture with a Philips screwdriver. Pull the fixture towards you to pull the attached wires out of the hole behind the fixture.
Twist the screw tabs covering the wires counterclockwise to remove them. Unwind the wires from each other. Place the fixture aside.
Twist the red wire from the motion sensor around the black wires from the two security lights; twist the white wire from the motion sensor around the white wires from the hole and from the two security lights; twist the back wire from the hole around the back wire from the motion sensor.
Twist screw tabs over each pair of twisted wires. Place the motion sensor over the hole in the wall. Screw the motion sensor to the wall with wood screws using a Phillips screwdriver. Place a security light to the wall on each side of the motion sensor. Screw wood screws through the brackets in the sides of each security light and into the wall with the Phillips screwdriver.
Angle the light arms on each security light so that they point down towards the area they are to illuminate. Screw a floodlight or floodlights -- depending on the make -- into the bulb socket or sockets on each security light. Return to the fuse box and restore the electrical power.
You may need a ladder to reach the lighting fixture where you will install the motion sensor and security lights.