Step 2: Getting it Assembled!
Like mortar, just fill in the cracks with the glue. I discovered gravity is great when used to your advantage, so don't let it fool you. Remember, you can move this thing however you want to as long as the glue is cooled and hardened.
Note: I wanted a more seamless look on the "outside" of the rocks, so I glued from the "inside". It doesn't really matter, just do it how you think is best.
IMPORTANT: Don't glue anything until you're sure you like it. Once it is cool, you'll have to break or cut the glue to do any rearranging.