For proper operation check that the units of measurement in the scene are in mm:
Customize – Units setup – System unit setup – mm
The carpet material is made using the Displacement card (make sure that Displacement is enabled in your scene settings).

2 carpet sizes in the scene:
-170*240 cm.
-200*300 cm.

https://staging.boconcept.com/en-us/p/form/155_170x240-1:59-2:10-18:5/

More carpets: http://3dsky.org/collection/shared/5321350