Advanced materials can be used to build equipment, and you can also rename signed equipment and sign unsigned equipment.

Create equipment. Advanced materials are divided into bound advanced materials and non-bound advanced materials. Equipment created by binding high-level materials is bound equipment and can be used by yourself and cannot be traded. Equipment made from non-binding materials is non-binding equipment and can be traded. As long as the equipment is built, it will be signed.

Modify the signature or sign unsigned equipment. When performing this operation, you need to bind the equipment first. After binding, modify the signature or signature operation on the equipment.

You said that advanced materials cannot be signed, probably because they are not bound. Or it may be caused by insufficient quantity or grade of advanced materials. You can go to the NPC equipment forger to learn more about the specific situation.