Remember GVA is a small airport, LX has one long-haul flight (the one you're on) operating from GVA. There is one (star alliance) business-class lounge and one first class lounge. Most people don't stay in the lounges for long and they're OK for that but not much more.
When you arrive you go through immigration. Before you get into luggage claim, go through the very small flight connexions security, up one floor to departures, then up another floor to the lounges. The first lounge is on you immediate right at the top of the escalators, the business lounge at the end of the corridor on the right going straight ahead from the escalators.