The patented plastic drain block raises your channel above the fixing substrate to create water drainage channels. Simply align the grooves in the drain block with the channel and then lay the channel over the drain blocks. Read the full installation guides here.
As a maximum, drain blocks can be stacked to a height of 20mm before being filled with sealant. The 5mm black must be used with the 10mm block to enable the sealant to be pumped in.