the shelf bracket cannot be placed in the slots directly above or on top of the screw if placing the bracket above the screw leave two slots open use a rubber mallet and gently tap from the top to feed the brackets into the slots repeat on the other side making sure the shelf brackets are at the same height apply plastic shelf clip making sure the longer side of the clip is facing the appropriate direction place the glass in and make sure the brackets glass and clips are secure cases come with left right and centre brackets for a full across shelf