If you don't have a car (which I'm assuming you don't), then you would take the bus from the Dolphin to Downtown Disney. There used to be 3 stops at DTD, but I think there are only 2 now - DTD Marketplace is the first, and Pleasure Island is the second - get off the bus at Pleasure Island, and walk through West Side. Cirqu is at the far end of DTD West Side. There used to be a bus stop at West Side, right near Cirque, but I don't think they use that one anymore.