Skid steer polesaw attachment - video

Skid steer polesaw attachment. 9:46 video:

https://www.youtube.com/watch?v=8yh36petZBA

Previously:

https://www.homemadetools.net/forum/...9677#post89811
https://www.homemadetools.net/forum/...9405#post89239
https://www.homemadetools.net/forum/...380#post116689
https://www.homemadetools.net/forum/...3100#post98061

My skid steer only has one aux circuit, which would handle the boom "stick" cyl.
How is the saw powered , turned on & off?