Viega 8330.2 Instructions For Use Manual page 19

Handling
Attach the bottom part of the block. Guide the threaded rods
through the guide rail of the Viega Mono WC block.
Attach threaded rods.
Place the upper part of the Viega Mono WC block onto the mounted
bottom part of the block.
Fit mounting angle.
Align Viega Mono WC block on the wall using a spirit level.
Mark bore hole and drill hole (10 mm).
Screw on mounting angle.
Viega Mono WC block 19 from 26