How to add a shadow to a person

I am still in the early stages of getting to grips with Davinici Resolve.
I record and videos on a full-size green screen that can capture a full shot of a person. I have really enjoyed working with Davinici Resolve and I have managed to get a really decent key and my subjects on to various backgrounds. The scenes however look very flat and I would like to know how to add shadows that mimic how the sun would cast; i.e. the light source comes from above and casts the performer's shadow on the floor. I have attached an image as a reference to the desired effect that I am trying to achieve.
Can anyone tell me if this is possible? Any help and assistance that you can provide will be most appreciated, thanks guys!
I record and videos on a full-size green screen that can capture a full shot of a person. I have really enjoyed working with Davinici Resolve and I have managed to get a really decent key and my subjects on to various backgrounds. The scenes however look very flat and I would like to know how to add shadows that mimic how the sun would cast; i.e. the light source comes from above and casts the performer's shadow on the floor. I have attached an image as a reference to the desired effect that I am trying to achieve.
Can anyone tell me if this is possible? Any help and assistance that you can provide will be most appreciated, thanks guys!