My new chandelier has what I believe are two grounds (1 copper, 1 silver), and two insulated wires (neutral and hot)but neither are marked. In the ceiling box is a white, black, and copper ground. How do I install the new chandelier with the existing wiring?

Sometimes they use the silver wire as a ground because it is more appealing with a clear wire. So, put the silver and copper to the ground in the outlet and connect 1 end to the strap or box. The chandelier wires are marked but not in the way you are accustomed to. If this is a clear zip type wire, common to chandeliers, note that 1 side has ridges and one is smooth. The ridged side is the neutral and the other smooth side is the hot. Hope this answers your question.