This was pretty easy to install. I just bought a bicycle brake lever from my local bike store ($15 for 2 levers) and a cable with the housing for $4. I got an additional screw tension adjuster for a brake lever to hold the other end of the cable housing (the part that sits in the engine bay) as you can see in this picture. I put two nuts on the back side of the tensioner, to make sure it doesn't come loose, the nut that came with the tensioner was pretty weak.
I then ran the cable through the fire wall and connected it to the brake lever. The lever just clamps right on to the shifter, i just put some rubber strips between the clamp and the shifter to fill the gap.
After i had the lever all hooked up, i measured out the length of housing that i needed and cut it to length (I pulled the cable out of the housing to make it easier). Then I ran the cable through the throttle body pulley, got rid of all the slack in the cable, and crimped on the end piece. I put 2 of them on, and a little washer, just to be safe. on the other end of the pulley, i put a zip tie around it to hold both the cables in the pulley. Without the zip tie, when the gas pedal is depressed, the hand throttle cable would get a lot of slack in the cable, and would probably eventually slip out of the pulley.
I couldn't find anything laying around, so i wrapped 3 zip ties around the bracket that the cable rubs on, to protect the cable from wearing down on the metal.
When i pull the hand throttle, it forces the stock throttle cable into the housing, so it doesn't kink the cable at all. Pretty much the same thing happens with the hand throttle cable when i depress the gas pedal.
Here is the overall view: