Bad Side of Town is a followup quest to Meet Citra main story quest. You are sent to town called Badtown to follow the visions from the previous quest.
Since there is a fast travel option for Badtown, traveling there should not be a problem. When you arrive you will realize that this town is the one from your visions.
Visit the bar.
Quest mark will lead you to a building at the east side of town.
Play a game of poker.
As soon as you enter the bar (house you saw in your vision), you will receive a new task. To prevent looking suspicious you will sit in a chair and play a game of poker with the locals. Locals you are playing with start talking about a snow white (you) that escaped from Vaas’ camp. Just when you sit in a chair, white suit man walks into the bar. After you do good in poker he approaches and commends your play. Soon after he leaves the bar and you decide to follow him.
Follow the man in white without getting noticed.
Following the white suit man without getting noticed means you need to stay in cover most of the time. He will, from time to time, check if someone is following him. Be on alert because if you are too far away from him 15 seconds timer will pop up and you will have only a few moments to get closer to him before the quest fails. At the end, he will enter a house at the edge of the village.