After doors are hung, close panels flat. On the back of door, measure the inner edge of the middle door 12 inches from the floor. Mark an identical measure on other inner door at the same height.
Hold bifold aligner level with both marks and make a pencil mark on doors at screw holes.
Drill holes for screws on both doors where marked.
Attach aligner with screws on both door edges. Do not tighten screws fully until after final adjustment. When doors are closed, the aligners on the center doors should overlap, keeping door fronts flush with each other.
Open and shut doors, checking for fit and alignment. Adjust if necessary. When adjustment is finished, tighten screws fully.