Schluter KERDI-SHOWER-LINEAR-TRAY installation tips…I use the compensation board to raise the height of the tray by 1 inch. This is necessary when using the KERDI-LINE-A adaptor that converts clamping ring drains to a linear drain. Then I set the shower tray. I use thin-set mortar to bond the compensation board to plywood and the shower tray to the board. All four perimeters of the tray should be level to promote proper drainage and make shower wall tile installation easier. Many thanks to Schlu