This isn't the first time I've installed drawers with slides, but this is the first time I've installed drawers with these soft- Install close rails. I will say that after the initial struggle I now understand a little better how to avoid some of these frustrations. Of course it is very important that everything is as square as possible, but you must not deviate more than a sixteenth of an inch from your measurement, otherwise you will certainly have to put spacers, since the lowering mechanism will not work. You also need to take the time to determine what exactly needs fixing i.e. a drawer or cabinet. The problem I was having was compounded by the fact that I was trying to install 12 sets of rails for some built-in modules I had. Installed in my daughter's room. I also had a slider where the plastic component that locks and unlocks the slider mechanism broke during adjustment, leading to the purchase of an additional set. I recommend you work through some of the workshop cabinets before attempting to install them for anything more sophisticated. you will thank me later.