What is the meaning of : "Drag down and hold" .
launch application, right click notify icon, select "radial menu designer"
the new window that opened, there you have those balls.
left click one yellow ball and hold left mouse button, move mouse to a gray ball while still hold left mouse button
when you reached your destination, lift your finger from left mouse button.
now you have dragged and dropped a ball.
does that answer your question?