how to specalize stem cells?

i'm not an expert in stem cell stuff, but i know enough ( i think)
so...
after you get the stem cells, how do you actually use it to treat, (cancer?)
how do you make it specialize to what you want it to be?

and if you can, can you make like an organ? like an extra kidney, if you already lost one, or a (virgina? you know what i mean, the whole thing, cuz some people wants to give birth from them, but not able to) or an arm? a forelimb?