A very simply. Get yerself an electrical outlet box, I prefer the mental ones. You'll also need a foot or so of extention cord cable...how ever long you need to reach your timer. This is sold by the foot at Lowes and Home Depot, I suggest using 12 guage, three cnductor. (black, white, green). You'll also need a connctor for the cable to box, has two screws and a "clamp" on one side, and threads on the other that look like the end of the lamp fixture. And finally you'll need a plug.

Much of this will depending on how you intend to mount the lamp inside the box, but you'll need to knock two of the plugs out. One to slip on the end of the lamp (take that washre off first, that's what holds the box to the lamp) the other for the extention cord cable... Make sure ya leave long enough to cut the outer coating off ans well as enough to mate the wires togehter... (white to white, black to black and green to green....and a pigtale to the box as well. From here you should pretty much be able to figure it all out...

good luck

Jaxxx