What are the initiating incident, the setup, and setting for Everyday Use?I still does not know the difference between these three temrs.

In Walker's "Everyday Use," the set-up (it's a noun and is hyphenated) is the way in which the writer has constructed and contrived the visit by Dee, about which the story tells.

The initiating incident (the visit) is a part of the set-up, as is the setting.  The story prepares the reader for the visit by describing the mother, Maggie, and Dee when she was younger; by revealing the friction between Dee and the other two; by revealing Dee's attitude toward the two and their home and their lifestyle, as compared to her attitude toward the outside world.

The set-up prepares the reader for the confrontation that occurs once Dee arrives.  The writer constructs the story in such a way that the relevant issues are revealed once Dee arrives.