@dres_actually
The easiest way to teach to use a bell is with the "touch" command. When it's time to take them out to potty, I give the touch command and out we go. They learn quickly to signal for pottying. If we go out and the dog lied, lol, no treat. Works easier with a female since the males' hollow leg lets them pee every time.
We do a routine with pups.. every time they wake up, eat, or play, immediately out they go.Once their bladders have better control, the bell makes it easy for one to signal if they need an extra potty. I hate the idea of them holding it in because they can't tell anyone what they want.
Here are Mary's instructions on targeting (touch). If you check to the left and right, she has a lot of other training instructions:
http://www.clickerlessons.com/targeting.htm