I have a small drain in my battery that, after a couple of days without starting the battery needs to be jumped. I bought a testing guage so that I could determine where the electrical drain is coming from but am not sure how to hook up to the battery. I've got a 2000 F150 Conversion van. Any help???

 

First there is always drain on the battery when the engine in not running.
The computer and other systems on the truck are still active such as computer memory, radio memory, keyless lock system and theift etc.
Your drain would be much larger in the ampere range.
Be sure your meter measures at least 10 amps to be sure it has enough measuring range or the meter will be damaged and or it's internal fuse will blow.
It is better to use lamps to find the fault, then use your meter to measure the final drain after the fault is found.
To use a lamp, get a few small power lamps, the socket to fit with pig tails.
Remove the battery cable and inset the lamp in series.
The lamp takes a certain amount of current to light it full brillience so you would know there is a drain fault.
As you remove fuses, there should be one that make the lamp go dim or nearly out. That is the circuit to suspect and go from there.
Note: remove the hood lamp for these tests or you will see it in your testing.