Now that it was wired up, I stuck my circuit tester into the plug at the other end and turned it on. The two orange lights mean that it's good! Yay!

The real test...an old lamp.

And it's good! (that's the dimmer switch that my hand is on, btw)

For some reason I don't have any pictures of what happened before this point. All I did was wire the outlets to the other end of the cord. They're marked which side is hot and which is return. Each side has two screws so that you can run a wire somewhere else if need be. I ran one to the second outlet. Same with the grounds. Then I screwed them into the box and put the cover plate on. As you can see, the thing says they're good.

The finished product, on my living room floor.

A close up. The black cord is my laptop, on which I'm writing this.

The switch. Turn to adjust brightness, click to turn on/off.