What's the agreement between Dourgen and Wu Sangui?

Dourgen and Wu Sangui agreed that after the Qing soldiers helped Wu Sangui defeat Li Zicheng, the north of the Yellow River was returned to Qing Dynasty, and Wu Sangui was made king. South of the Yellow River belongs to the Ming Dynasty, and Prince Chongzhen (or Kings) was established in Nanjing. Dourgen led an army to enter the customs with one soldier and one pawn, realizing the unfulfilled wish of Manchu nobles for decades.