So I bought these Chrysalis wall flats on craigslist because I thought they were awesome and would add some visual interest to my walls. Unfortunately, the installation instructions call for some heavy duty adhesives that would certainly leave a mark when removed. So, we decided to install them like a painting (rather than filling up the whole fall) by using a foam board backing. Here's how.
Step 1: Buy foam board (from Staples, etc.). Measure the layout of your wall tiles and cut the foam board to match. Tape the foam board together with duct tape.
Step 2: Stick some really sticky double sided tape to the back of the tiles. Duck brand double sided tape is good.
Step 3: Start sticking those on there. Start in the corner and line it up nice and straight. Place the tiles down one edge at a time, then commit and press it down flat.
Step 4: Keep going! Lay them all down flat.
Step 5: To hang it on the wall, you're going to poke holes in the back of the board. These are going to line up with nails you'll put on the wall. Poke the holes into the foam board using a knife or corkscrew. Go slowly as to not jab into the wall tiles on the front. To make sure it's all in order, you can use painters tape.
Step 6: Put painters tape over the painters tape on the back of the board - sticky side up. (If you just peel off the tape from the back of the board and then press it on the wall, it will be inverse.) Mark where the holes are. Then put the marked tape on the wall, using a level to make sure it's even.
Step 7: Hammer nails in at an angle in the marked spots on the tape. Carefully lift up the board with wall tiles and press it against the nails until it clicks into place.