I have a wood burning stove in my pole barn. I have add a blower to it and want to control the blower to turn on & off by way of a thermostat. Could anyone help me with this?

If you added what is called a fan center (relay and transformer) in the electrical circuit to your blower, then you could add a standard 24 volt thermostat .
Another way to accomplish this is to install a line voltage thermostat (120 volt) in the electrical circuit to the blower.
Not knowing how you want it to work I will offer another option, you could install a temperature operated fan switch in the stove, this would bring on the fan when the stove reaches a predetermined temperature and shut it off as temperature falls. Good luck, Mike