The way to define requirements class
STEP 1 Find the menu path to get into transaction code OVZG
Follow the menu path “SAP Customizing Implementation Guide->Sales and Distribution->Basic Functions->Availability Check and Transfer of Requirements->Transfer of Requirements->Define Requirements Classes” in “SAP Reference IMG” interface. If you want to know how to reach “SAP Reference IMG” interface, you can read our article http://www.nicesap.com/ps/how-the-reach-sap-reference-img-interface.html
STEP 2 Select a requirements class you want to copy, then click the “Copy As…” button or press “F6” button on your keyboard.
STEP 3 Input the name of new requirements class, such as “Z46”, and change the configuration from “+” into “*”, then save the requirements class.