Wiring an outside light is fairly easy once you have the light ready for installation. Wiring is the easy part but mounting is the difficult part but heres the steps.
Wiring an outside flood light is simple yet the mounting takes time. To install and wire an outside light...find the location of where you need to install the light. This may be a light to be installed outside a garage so Ill explain how to wire and install this. First locate the power source you are going to use. This may be a junction box in the garage that is used for other outlets or lights. Tap into this with 14/2 wire.
Tie the wires together with the new wire to the junction box wire. there should be 2 wires a black and a white...hot and neutral. A third wire is a bare copper wire which is the ground. This ties with the ground wire or green wire in the box. Run the wire along the rafters until you get to the place you want to punch through for your light. You will have to drill a hole about 1/2 inch using a hand drill or something similar with a large bit. Once this is drilled you are ready to install the light fixture.
Take the fixture and mount this to the outside of the garage, the wires should be pulled through the back of the hole and tied to each wire accordingly. You can set a junction box over the hole to have the wires inserted in when you are finished wiring the fixture. This is not a hard project but does entail some work...2-3 hours. When installing make sure to turn off all power at the panel and turn back on when finished installing. If in doubt contact a qualified electrician.