Hello, where can I get/find xian tourist buses?

I'm not sure where you are going, but most of the tourist buses leave from or pass by Railway Station.
As I know, the nearest station that you can find a tourist bus is Xincheng Square, and you can walk east along the Nanchang Street for about 2 minutes and turn left at the first crossing, then walk north along Nanxin Street for about 3 minutes, you will see the square, cross it to the north gate, you will get to the station for Tourist Bus 7.