Apply mortar to the mortar bed, the Zero® brick’s special recess. Make certain that the mortar does not touch the front edges. You position the next course of bricks with a turning tilting movement from the front towards the back in order to distribute the mortar over the mortar bed. This pushes excess mortar backwards where you can scrape it off with a trowel. Thanks to this tilting technique you avoid mortar remains at the front of the brick.