An example to work with would make this easier to answer.
The bounding box should be fairly straightforward: just take the min and max of all your vertices for each coordinate.
Depending on the geometry of your model calculating the volume is either almost trivial, or extremely difficult. If your model is only convex you can use a point inside your mesh and calculate the volume of each tetrahedron. I believe there is a FEX submission that does that, so if you have a convex shape, I will look it up for you.