The side channels give vertical guidance for Keeping the glass panels in place. Evaluate and mark where the pre-drilled channels should be set up on to the shower partitions. Drill pilot holes in the walls using a masonry drill little bit. Make sure the channels align flush to your partitions. https://showerdoorinstallationnew03692.blogsidea.com/39178353/5-tips-about-shower-door-installation-near-newton-ma-you-can-use-today