you missed copying
"Using the thin-bed method and following all applicable industry standards, set the tile or stone covering directly on the Schlüter®DITRA 25 in such a way that the tile adhesive becomes mechanically anchored in the square, cut back cavities of the Schlüter®DITRA 25 matting.
notice the mechanically anchored and not chemically fixed.
but if fitting, say gulf stone who recommend a two part adhesive or the TM equivalent as favoured by many members on here, Schluter say you mustn't use these adhesive on ditra due to these adhesives bonding / chemically fixing to the plastic and stopping the product uncoupling.
Also care should be taken if laying tiles "immediately" after laying the ditra. un-cured adhesive sticking the ditra mean tiles can't be lifted without pulling the ditra up.
