Sealey GSS2323 Instructions Manual page 8

Now fit 26I, 26H top channel and 26C, 26D bottom channel to the sheeting by tapping it in
(diagram A) or sliding it in. (Diagram B) Note that the small lip of the channel is always facing
out. This is to ensure that rain water can not build up inside your shed. Make sure 26I and 26H
are used as top side channels.