I assume the problem you are having is mounting the sliders to the side of the case, not the drawers.
I find the easiest way is using a scrap wood spacer. I start at the top so if I make a mistake somewhere it isnít carried or transferred to other sliders.
Cut a spacer that places the slider where you need it for the top drawer. Make sure that the spacer is wide enough it provides support for the entire slide. Place the slider on the spacer and screw in place. Move the spacer to the other side and mount that slider. Now both sliders are parallel and level.
Work your way down, cutting the spacer piece to fit.
Last edited by Terry Q; 12-27-2019 at 03:13 AM.