Very basically all Yorkstone paving should be laid on a full wet bed of mortar over a compacted hardcore or concrete base, deep enough for the site conditions. We have a great deal more information available on our natural stone paving installation guide that can be found at the link below:
Due to the thickness of Yorkstone paving, it is quite common to see this type of paving laid on sand or grit, with only the edges of the paving concreted into place. This is only a suitable method of installation if there is no chance of movement within the sub-base and surrounding features.