Alright, I understand how to do everything, except the whole cranking the engine thing. Once I put the tester in there, then what exactly do I do? TIA.

After you have the fuel and spark unhooked then get in the car, hold the gas all the way down and try to start the car. Of course it won't start but the engine will crank. Have someone hold the gauge and tell you whan it stops moving. It should be like 4 engine revolutions I think.

Unhook the fuel and spark...? Do I just take out the fuse for the fuel pump, run it til it dies, and then take out all 4 plugs?

Simple easy way to do it is...
Start your car and drive around or let it idle for about 5 minutes (or until normal operating temp). Disconnect the 3 relays in top right part in your engine bay (driver's side). It's just three little boxes lined up in a row, just disconnect those. Take the plugs out, put the test in, crank the engine for about 4-5 seconds (Don't keep cranking it, hold it for 4-5 secs), the needle should stop moving. Take out test and test the other 3 the same way. Also, visit this website for pics and whatnot.
http://www.2gnt.com/www/corbin/comp.html

What if I don't have a torque wrench? I have heard that I could just put the spark plugs in as tight as possible, with only using my hands. Is this true? And if I decide to replace my plugs, what kind do I get? TIA.

put them in hand tight, then use a socket wrench and do 1/4 of a turn.