Instructions
Click "Build" to enter build mode. The icon features a picture of a paint roller and large saw.
Click on the tiled flooring in the picture of a cutaway house.
Scroll through the available options and click on the pattern you like. Clicking the tabs at the top of the build menu will take you to different styles of flooring, such as tiles, stone and wood.
Hold "Ctrl" and press "F" once you have selected your flooring. Hover your mouse over the area you wish to place the flooring. The flooring will be in the shape of a triangle instead of a square. Click to place flooring.