How do I place an order with Duo Deals?

There are four ways to place an order with Duo Deals: A) start a deal and invite a friend to buy together, B) accept an invitation and buy a deal with a friend, C) join a deal and buy together with another user, and D) To buy alone.

A. To start a deal and invite a friend to buy together

B. To accept a deal invitation and buy a deal with a friend

C. To join a public deal and buy together with another player

D. To buy alone