Step 4: Begin gluing.
Since we were covering our table with clear resin, we weren't too concerned with the type of glue used. I started out with contact cement, moved on to furniture glue, then Liquid Nails for small projects, and even tried siliconized caulk. I ended up using plain old super glue. This was the best option and the one I suggest for you. Since the caps are going to get covered with resin, they just need to stick to the table, so a couple of dots are all you need. Don't go crazy, because messy excess glue will show through the resin when you're done.
Extra information regarding this step:
Although I suggest super glue for this project, the contact cement was truly the strongest adhesive. However, it took some time to use and was less forgiving. The silicone-based glues (Liquid Nails and caulk) seemed to shift or expand as it dried, which ultimately threw our design off. Super glue was the least elegant choice, but it dries relatively quickly and was rigid enough for this project. One note of caution: I discovered that Super Glue reacts with the hexane/toluene base of contact cement. They discolor and create a crystalline growth that resembles a fuzzy, white mold that must be removed with acetone. So pick one glue and go with it to avoid this kind of situation.