Spread out the underlayment, shiny-side down (Image 1). Pull it tight to the edges and cut off the excess with a utility knife. The next piece of underlayment goes right next to the first. Make slits in the material to go around objects such as plumbing stubs. Continue until entire floor is covered. Tape around the edges and along the seams to keep the mat from moving (Image 2).
Start laying the tile with full pieces against the wall starting in the corner that is most apparent when entering the room. This ensures full tiles will be the most visible. The edges will eventually be covered with base molding, so a small gap is fine.
Snap the remaining tiles in the row until you meet the wall at the other end of the row. Cut the final tile to fit the room.
Because tiles come in sets of two, cut one tile in half and start the second row with the half tile. This ensures the snap together joints are offset between rows. Snap the half piece in place to begin the second row (Image 1) and continue with whole pieces of tile finishing the row with a custom cut tile (Image 2). Alternate starting each new row with full and then half tiles so the seams are staggered between rows. For angles and curves, cut tiles using a jigsaw.
Cut the tiles for the final row to the correct the width and snap in place. A small gap with the wall will be covered by molding.
Use the tile manufacturer's recommended grout, specific for snap together tiles.