Locate the studs in the walls to which the cabinets will be installed. Mark both edges of each stud with the pencil and use the yardstick to transfer the markings up and down. Locate the predrilled holes in the back of the IKEA cabinets. Take note of the vertical location of these holes in reference to the positioning of the entire cabinet.
Hold the suspension rail tracks up to the wall at about the level that you wish the cabinets to be, taking into account the position of the suspension rail on the cabinet and the way that affects the final position. Set the level on top of the suspension rail and adjust the rail until it is level. Mark screw locations at every point where the rail overlaps a wall stud. Predrill these holes and attach the suspension rail to the stud using wood screws.
Slide the custom suspension rail bolts down the rail and arrange them so that one bolt goes through each hole in the first cabinet. Secure the cabinet to the rail with nuts and tighten the nuts with a socket wrench almost all the way. Repeat this procedure until all cabinets have been installed.
Inspect the cabinets to make sure that they are evenly installed. Rearrange depending on whatever adjustments need to be made. Tighten all nuts completely once the cabinets are in their final positions.