Giving change from a coinco s75-9800

Pardon my newbie question, but I have a Coinco S75-9800 mechanism in my Vendo machine. It works fine, but it doesn't give change. My guess is because there's no change in it to give out. How do I fill the mechanism with dimes and nickels to work as change? I see that there are two long verticle tubes. Are these for providing change? If so, how do I prefill these tubes with dimes and nickels?

Thanks for the advice.
Dale

[MoonDawg]

The two hoppers hold nickels only. The first nickes dropped in the coin slot start accumulating in the hoppers until the hoppers are full. It's simpler to give 3 nickles back, than 1 nickel and 1 dime

Thank you very much. I'll give it a try.