Using a perspective camera in a 3D world...

Given:
a frustum with values FLeft, FRight, FBottom, FTop, FNear, FFar,
a desired vertical FoV (VFov)
aspect ratio (AR) (defined as WindowWidth/WindowHeight)

... how are the VFov and AR applied to the frustum? I'm working with code that only allows me to set the frustum of camera.

EDIT: No replies... is what I ask even possible?