Step 1: Prepare.
To do this the way I did, you'll also need the following:
- one bike
- one cooler. I think this is what I used: http://www.rubbermaid.com/rubbermaid/ecommerce/product.jhtml?prodId=HpdProd200006&catId=HpdCat190071
- one steel right-angle bracket
- an electric drill and various bits
- something to attach the cooler onto the frame: I used the kind of brass bracket that slide bolts (for doors) slide into: see http://www.lowes.com/lowes/lkn?action=productDetail&productId=73299-1277-SP1271for example. You could also use the kind of copper bracket they use to hold copper pipes against the wall.
- various bolts, screws, and bits of chain
- you might find it useful to have zip ties to temporarily hold the cooler in place while you try it out.