The north African takes the gold the west African left
The north African then drops the salt that they brought along which usually was greater than the amount of gold that was left
The north African then beats the drum signaling to the wets African that he dropped off the gold
The north African then leaves the site with the gold
the west African comes to the site
The west African leaves the site with the salt, ending the trade. If he is happy, they continue to trade. if not, the west African can stop trading with the North African. This can also go for the north Africans as well.