Typically (but not always) you'd have an overhead softbox, slightly behind and pointing a little forwards. A boom arm is the best tool for holding it, but you can manage without one if you have to.
Then a key light, either with a reflective umbrella or a standard reflector (you need a choice of both) will cover most situations, place it wherever it produces the right kind of shadows, and control the hardness of the shadows by choosing either of those tools and adjusting the distance.
This can be done with hotshoe flashes but studio flash is a much better choice. The
SmartFlash twin head kit with a 60 x 60cm softbox (you'd need a much bigger one if you wanted to shoot highly reflective subjects) has everything you need, but the SmartFlash is out of stock right now - give it a few days and they'll be back.