Whoah you guys, thats a lot of information for my tiny brain.

Heres some background info.
What I'm trying to build is an Adjustable Map (Manifold Air Pressure) Sensor for my Jeep. The map sensor calibrates the fuel delivery to the engine. I have some engine mods, and am running a little lean. So the solution is to change the voltage slightly thats supplied to the stock map sensor, this in turn witll supply more fuel to the engine.
The idea (I think) is to install this module inline to the stock map sensor, and then you can switch it to active or inactive. That way if it fails you wouldnt get stranded.

I could buy one for a little over a hundred bucks, but somebody pointed me to some websites that (sort of) illustrate how to build one myself. Parts were about $20.
Figured it might be kind of fun, and I dont really have much experience with this kind of work, so it might be good practice (or a complete disaster).
Here are the links to the websites:

This is the original site

And this site sort of expands on the original.
This is where I got that diagram.

I already bought all the parts.
This is what I got from my friendly neighborhood Radio Shack:

Multi-turn Cermet Potentionmeter 1000 ohm
LM317T Adjustable Voltage Regulator
220 ohm metal film resistor
Circuit Board
Heatsink for Regulator
Housing for Project
SPDT toggle or rocker switch
SubMini LED Lamp

Does that fill in any gaps?
Thanks for all the info, and any other bits you think might help.

Have I sufficiently illustrated how clueless I am yet?