How do I solve questions of the following type:

Find the bounded volume between:
The plane z=0,
the plane x/4+y/2+z/4=1,
and the hyperbolic cylinder x=2y^2

I want to know what is the way to solve these kind of questions. How do I draw it? What are the steps for solving such a question?

In addition, since I have a big problem with drawing, I will be very graeful if someone can tell me how to draw a cube inside a spere. What are the steps?

Any kind of help will be extremely appreciated.

Thank you in advance.