Clean the Floor and Dry Fit the Tiles
Thoroughly clean subfloor. If subfloor is wood, install cement backer board to stabilize it.
Start in a 90-degree corner. Lay out tiles in a dry run to make sure they fit.
Using a wet saw, cut one tile into a triangle diagonally from opposite tip to opposite tip. Lay half of first tile with cut side facing 90-degree corner and tips almost touching walls at a 45-degree angle.
Trace tile on subfloor with pencil.
Using first tile as a guide, lay out remaining tiles, using spacers to allow for grout joints.
Parallel guidelines on floor will help keep tiles straight. Set partial tiles on top of and overlapping whole tiles; then mark cut lines with a wax pencil.