Lay two intersecting lines across the subfloor, using your chalk snap line. Square the lines against each other with your carpenter's square and adjust them as needed. You should end up with four squares on the floor, meeting in the middle.
Lay a few square feet of thin-set mortar over the intersection of the two lines, using your notched trowel. Set the first brick face tiles in place, using the lines as guides and spacing them with your wood shim.
Build out from the center, staggering the rows of bricks, so the narrow ends of the bricks meet at the center of the long side of the brick on the previous course. Install all the tiles and cut the ones at the edges (by the walls) on your wet saw. Let the tiles set overnight.
Brush tile sealant over the tops of the bricks, making sure not to let it pool in the spaces between them. Allow the sealant to dry for a day.
Grout the floor with your grout float, pressing the grout into the spaces between the brick and squeezing it off the face. Let the grout sit for about five minutes, then wipe off the excess with a damp sponge. Allow the grout to set for four to six days.
Brush sealant over the whole floor, including the grout lines.