You can read in the user instructions in your invitation pack how to take the sample or you can watch this video:

You send your stool sample, along with the participation form, in the enclosed padded envelope. A postage stamp is not required. Your stool can only be examined if the participation form has been fully and correctly completed. Please send your sample as soon as possible. If that does not work, store it in the refrigerator for up to 14 days.

The lab will analyse your sample. You and your GP will receive the result within two weeks. The collection kit and the lab examination are free of charge.