Fine, fine. Please, don't yell at me. I may be stupid, but I try to follow your advice. You can see in the screenshot that I have changed SubItemTypeName-field. Tongs appear in the surface, but can not be interacted with. I also tried couple of more names, but with no success.
I understand that newbie like me with newbie problems can be irritating in the eyes of more experienced users, but I'm not irritating on purpose. I'm just glad someone has time to try to help me.