First, you have to run the turtlesim_node from the turtlesim package:
$ rosrun turtlesim turtlesim_node.py
Second, you have to run the turtle_controler node from the turtlesim_control package:
$ rosrun turtlesim_control turtle_controller.py
After that, you will be asked for a new X and Y turtle position on the terminal. Then, the turtle should move to the specified location.
You may customize the PID controller by changing the angular and distance coeficients from the init() method in the turtle_controller.py file.