Porch lights add safety, security, and style to an entryway. They illuminate steps and help you see callers before you open the door. You need to supply power and install an interior switch, projects described separately on this site.
About 6 hours to run cable, install fixture and a switch
Voltage tester, drill, 1/4-inch bit, jigsaw, fish tape, drywall saw, screwdriver, strippers, long-nose pliers, lineman's pliers
Locating studs; cutting into siding; stripping, splicing, and connecting wires to terminals; installing boxes; running cable into boxes
Fixture(s), outdoor box(es), two-wire cable, interior switch box, switch, electrician's tape, caulk, wire nuts, bent coat hanger
Support the fixture with a wire coat hanger. Connect the ground. Splice the white lead to white wire and black to black. Fold the wires into the box and install the fixture onto the mounting bolts. Caulk around the base. Wire the switch, install a bulb, and test.