You have to rank up to Jr. Member to to make the signature.Or you could make signature for yourself 
If its only about creating signatures then its fine regardless of the rank, he can create for all ranks but he can't wear any of it. Settings - Signature
I also assume that he's talking about making one, not wearing. All of the tutorials for creating signatures has been given already. And he can test those signatures by posting it and probably create a test thread on Archival.