Desire Wedding

My soon to be wife’s wedding ring is a 2 piece set: engagement ring and a wedding band. How do I exchange rings during the ceremony? Should she already have the engagement ring on, and I just add the wedding band? Or should both her engagement ring and wedding band be on the ring pillow [...]

And what should a wedding band look like? How can you tell the difference from a normal ring to a wedding ring? Are wedding rings always made of gold? How much should a simple wedding ring/band cost?