My flight Shanghai-Zurich/Zurich-Lisbon. I've one extra bag, not oversized. How much does it costs?

I leave on Friday. I have 14 hours scale in Zurich: arrive at 15.50 and departures at 6.50 the day after. How can I be sure that your company won't charge me twice? at the departure in Shanghai, and at the airport in Zurich? I will spend one night in Zurich, outside the airport. The luggage can be at the airport and go directly to Portugal the day after? Should I ask and set all this things at the airport in Shanghai? Thanks and hope the answer ASAP.