Each one of your chrome intakes should have an allen bolt on the outside. The inside bolt will probably be the factory hex head bolt. All six of those allen bolts should have a thin washer under each one. The left side has an extra allen bolt with a spacer. Here is a picture with the covers off.

The easiest way I have found to reinstall them is to pull all the plug wire boots and fit the plug wires in the slots. Push the covers down and attach the plug boots one by one. Tighten down the allen bolts with washers on them and viola you are done!