I have always used my stellas with the regular, round knobs but have a new one I would like to put the power knob on. Trouble is, I can't for the life of me figure out how the get the old knob off an the new one on! There are no directions anywhere with the reel and I don't want ot screw something up. Are there any special tools required or is there someplace where directions might be posted? Anyone wanna talk me through it?