A rotary phone should be easy to figure out within a minute or so.
You didn’t watch the video at the link did you? These kids kept hanging up the receiver before dialing. LOL
I had seen it before, seeing the rotary and the letters and the finger holes and playing with it a second should lead a normal person to put 2 and 2 together and figure out how to enter the numbers, and the receiver doesn’t have any buttons or controls, just the obvious off and activation button when placed in the holder.
People are always having to figure out new controls in cars, on equipment, on new phones.