Lost instructions. How do I find out how to install?

It's actually pretty simple. The half round hole is for the bare or green ground wire, the "L" shaped slot is for the white neutral and the two remaining slots are for the two hot wires, black and red. You need either a 2-gang deep box or a 4" 1900 box with a 2-gang plaster frame to mount the receptacle in. If you have any further questions you could consult someone in the electrical department of your local Lowes store.