How to use home-grown Stevia?

Following another member’s example here (I’m sorry, I forgot her name), I bought and am growing a stevia plant on my deck. It’s growing, er, like a weed, but now I don’t know what to do with it! I picked a leaf one morning and put in in my coffee, but it didn’t do anything. I suspect it has to be crushed up in some way, but I don’t know what.

Could anyone who grows their own stevia help me with how to use this exuberantly growing plant to sweeten things?