I use 6-12 hen mallards.
There are a few companys that make teal calls; duck commander, haydels, big guys best. You blow them similar to the way you blow a mallard call. It's got a real high pitched sound, it almost sounds like a little kid laughing.
Teal also whistle, which is an easy call for most people to duplicate. They'll come in to mallard hen calls too.
If you got anymore questions don't hesitate to ask, it's the best way to learn. :cheers: