Here's the subfloor going down. It's pretty easy for the most part. Just line the tiles up and bang them in place with a rubber mallet and 2x4. You have to be careful at either end to make sure you leave at least 12 inches of tile. You also want to stagger your seams for stability. I ended up using a ramset powder actuated gun to secure my tiles to the concrete once everything was set. This helped to level out slightly uneven spots in the concrete.