Decide where you want the cabinets to be. Consider the height and the amount of clearance you'll need for other items you may store above or below the cabinets.
Draw a line marking the bottom edge of the cabinets. Measure up from the floor at several locations, mark the wall, and check the line to see if it's level by using a carpenter's level. When the line is level, mark it with a pencil.
Nail the 1-by-4-inch board to the wall so the top edge of it is even with the line you've drawn. This board will serve as a temporary support when you place the cabinets.
Place the first cabinet against the wall, resting the bottom edge on the board. Check to see that the cabinet is level and plumb, then secure it to the wall using wood screws. The screws should be long enough to sink 1 1/2 inches into the studs of the wall.
Place the next cabinet on the board, snug against the first cabinet. Secure it to the wall as in Step 4, then bolt the cabinets together using a nut and a bolt. Repeat until you've installed all of your cabinets.
Remove the 1-by-4 board from the wall.