The little spring goes behind the base-plate
Either pop them or weld them
The coil ends of the spring should be against the backplate and the x-section of the spring should be farthest away from the baseplate
This way, you can bend the spring to tighten the DZUS-es (depending on the thickness of the panel)
The quarter turn unit goes on top of the panel and can be pop riveted
You should slightly turn the the "quarter turn unit" so that it's rivets don't interfear with the rivits that hold the spring onto the baseplate (otherwise you won't get a nice flush fit of the panel)
Got no pics, so I hope this makes any sence
Do a search for "dzus"
There was a similar thread not too long ago with some pics
cheers,
Jeroen