Wall cabinets are securely mounted using double mounting rails. The placement of the mounting rail depends on how far from the ceiling you want to install the wall cabinet. The distance between the top of the wall cabinet and the top edge of the upper rail is 110 mm. The lower rail should be mounted 190 mm below the upper rail, measured from the top edge of the upper rail to the top edge of the lower rail.
Use a level to check that the cabinets are straight both horizontally and vertically. Also, ensure that the angles between the cabinet frames and the wall are exactly 90 degrees. Adjust as needed to achieve a stable and accurate installation.
If you are using a wall cabinet as a range hood cabinet, it may sometimes be necessary to adjust the back panel of the cabinet based on the range hood you have chosen, or in some cases, to remove the back panel entirely.