I watched a bunch of videos on Manfrotto 131 Arm. This is the best in that explains attaching the arm to the tripod and camera. Thanks

What type of tripod did you use with your arm?

I agree, poorly made video :) Demo was tedious too, unplanned at best. Instead of rotating the entire arm starting at 0:43 to screw onto base, you should've just placed the head onto to tripod and rotated the grey/silver knob to tighten, not the whole arm! That's what that knob is for. Then starting from 1:41, what you are trying to demo, is totally out of the frame. Should've brought it to the center of the frame, or moved the camera back a bit so the entire arm fits.