There’s a lot of information left out in this question, so I’m going to make some assumptions.
Did you move into a house with an existing system with the speakers, wiring and switching installed but no source equipment? Mostly likely the prior owner took all the source gear and left the parts that were installed in the wall. If that’s the case, that’s actually a good thing because the hard part of wiring has already been done.
That’s what it sounds like to me from your question. First, you need to find out what all those switches are connected to—where the sources go and which source switch controls which zone.
As far as what equipment you need to take advantage of this, that really depends on what’s already there. A music server like the Mirage MM-5 is excellent. Then you’d need a multiroom amplifier ... but you need to find out the preliminary info first. My advice is to consult a local CE Pro who can look at your home and determine what’s already happening and offer suggestions.
EH has a searchable directory of installers here: