Lining up the screwholes is the critical part. The rails must also sit on the plastic glass trim.
Some people use low tack adhesive tape placed over the rails and body while it is in position, but the adhesive strip is not peeled. Basically, the side rail is in position to test. Then you are ready to peel the adheside strip, fold over the siderail - like a piano cover (but in reverse). Unpeel the adhesive strip and then close the piano ! Remove the low tack adhesive strip.
The method I use is a lot simpler. Place two screwdrivers on each hole in the siderail. You are only interested in the orientation of the screwholes, so practice placing the siderail into the cabinet. You will see in line up. Once you know what you need to do, remove the adhesive backing, and then do exactly what you did during the practice run. With the screwdrivers in the siderail holes, you can align the moving siderail. Helps when there are two people, but I've done a few before without any issues.
