Sweep or vacuum the concrete floor to remove dirt and dust. Mop the floor with water and a mild soap. Allow the floor to dry. Carpet tiles affix better to clean, dry surfaces.
Measure the length and width of the room with a tape measure. Mark the mid-way points of the length and width with chalk.
Draw a straight vertical chalk line, using a chalk line reel, starting at the length midpoint to divide the room in two. Draw a straight horizontal chalk line at the width midpoint to divide the room into quarters.
Place a carpet tile in each of the four quadrants so they all touch the midpoint of the room. Create a pattern of rows outward from the four centered tiles.
Peel the backing off the carpet tiles one at a time or add one dollop of releasable adhesive onto each corner of the tiles.
Line each tile flush with the one next to it. Apply pressure so the carpet sticks to the concrete floor.