Step 7: Cover with resin.
I won't get into how to mix the resin since there are instructions in the box, not to mention ample tutorials available online. UPDATE: The resin I used was Envirotex Lite Pour-on High Gloss Finish. You will, however, need to spread the resin to get into the gaps between the bottle caps as well as out to the edges. This is why your caps need to be glued down, as you will be running a rigid piece of paper or plastic over the surface of the caps. This is a great opportunity to use those fake credit cards that come in your junk mail. I used an old insurance card, but any stiff plastic or cardboard would suffice.
Remember that the resin will level itself out, so just make sure you have enough to fill in the gaps and even out any high areas. You may want to cover your work to keep any random hairs or dust from getting stuck. Now walk away for about 7 or 8 hours.