Ask HN: Quaternions to Euler angles i.e. (roll/pitch/yaw)

I have a position of the body. Its position is [x, y, z] and orientation as a quaternion vector [q0, qx, qy, qz]. (Note: This is defined in world frame of reference.)

Now, I want to convert this to orientation to a rotation matrix which transform a point from body-frame to world frame.

I haven't found exact definitions for this kind of conversion. Everybody just talks about rotation in general. And when orientation is defined, it is very difficult to get its detailed definition. I will really appreciate if anyone will provide a precise definition for this transformation?

Thank you.