you will need;
a PSU, - if you figured this one out, you have the brain cells to complete this instructable
Wire Strippers / side cutters or cigarette lighter, anything you can use to remove some of the plastic off the
some cheep electrial wire (can be ripped from Ethernet cable) i got mine fo ÃÂÃÂ£0.80 (just under $2) from rapid electronics
optionally you may want a soldering iron and some solder.
Step 1: The first bit
basically strip the plastic coating of both ends of the wire to expose the bare metal core.
Step 2: The main stuff
turn the PSU off on the back of it, purely because some PSUs wont turn on if you do the next bit first then this! and you'll have to do it in the right oder.
look at the first image, you'll find there will be a green wire (similar to the one under my thumb) there should only be one, how ever i have seen two before (as on this one) you want the lighter green one.
You'll see that this connects into the plastic part of the "plug." in the plastic plug at the top there is a bit of metal it will be hollow, stick one of the bare ends of wire into that.
next stick the other end into any of the black wires, there are a few so take your pick.
find the rocker switch at the back of the PSU (not all PSUs have this so you may need to turn it off from the mains in the first place) turn it on. the fan will start the PSU will supply Power to all the components connected.
Step 3: Read this bit.
IT is important that if you want to connect any components after you've tested your jump started PSU that you switch it off via the mains first then add what ever component you want to then turn it on. if you turn the PSU on then connect the molex adapter to the advice, you will create a nice blue spark and cry when you realise that the component is now dead.
same goes when you are building a PC.
also if you want a 12v supply with upto 5 amps you can cut the red and black wires free (sounds like bomb disposal) of the molex and strip the ends. this will give you a nice supply for what ever.