This is common in Federal laws.
A good example of this would be interstate highway standards. When you drive from one end of the country to the other and notice that all the road signs look the same, it isn't because Congress sat down one day and passed a law with detailed requirements for highway sign colors, letters, spacing, etc. More likely, Congress just passed a law requiring all interstate highway signs to have uniform standards that would be established by the Federal Highway Administration.
That’s what I’m trying to determine, what specifically the law says. If it uses the term “gun dealer” without any definition, or if it has some specifics. Trying to see how far Obama stretched the law, and whether he created it out of whole cloth or just gave it an expansive interpretation. I don’t have expertise in gun law and regulation.