Where do you put the ground straps and what are these for

 

They are to prevent static electricity, put it on a known good ground like a bolt on the chassis. They are a must if you are dealing with electronic equipment like circut boards.

 

The engine block needs to be connected back to the battery ground in order for your ignition (spark plugs) to fire (complete the circuit). The ground straps connect the engine back to the frame/body panels that the battery ground ties to. The stock straps on the driver's side connects to a bolt in the front of the head just behind the coil.

 

Here's a photo of the ground strap on the passenger side thanks to Shoebox:

http://shbox.com/1/battery_cable_ground.jpg