Underlayment

• It's crucial to have strong underlayment that won't move and won't soak up moisture, or the tiles will crack. Lay 5/8-inch cement board over the entire floor, securing it with thinset mortar spread with a notched trowel and screwed down. Fill the seams of the boards with mortar to smooth out the edges where they connect.
  
  

Tiling

• Lay your tile from the center of the floor. Divide the room in half in both directions with a snapline and use those two lines as your guides. Build them off each other, setting them on the floor with thinset mortar and leaving about 1/4-inch of space between them. Plastic tile spacers are good for consistency, but make sure to pop them out with the tip of a flat screwdriver before you grout. Lay all the full tiles that will fit in the room, then let them set for a few hours.
  
  

Cutting

• Unlike harder natural tiles that require a wet saw, straight-cutting ceramic tile is easy. Mark the tile with a pencil at the size you need. Lay the tile on the tile cutter with the small circular blade over the mark. Drag the blade over the surface of the tile, pressing it down just hard enough to lightly score it. Press the prongs of the cutter firmly down on either side of the line until the tile snaps. Lay the cut pieces with the cut side facing the wall. Use tile nippers to cut out small chips or corners to fit the tiles around pipes and other obstructions.
  
  

Grouting

• Once the tiles have set for a day, mix your sanded grout according to the instructions. Apply it to the floor with a grout trowel, pressing the grout into the lines between the tiles. Let it set for about two minutes, then wipe the tile surface with a damp sponge, smoothing out the grout in the lines without digging it out. Let the grout dry for three or four days, then use a liquid sealer on the exposed grout so it won't absorb dirt or moisture.