Visited on July 12, could not charge.
The charger is under the roofed area. You can enter from either the back road Moosgasse, or from the main road Surentalstrasse when driving south, there's a gas station sign and quick access slip road that will also give you access to the charging station.
There 2 groups of 2 parking spaces with EV symbol + "Kunden". The GreenMotion AC chargers don't have any marking and don't seem to appear in any app, so they are probably not public.
The DC charger is a Compleo with CCS and AC socket. There are instructions with a QR code on the front, but that only works for the CCS. If you want to charge ad-hoc on the AC you'll have to guess the URL.
Both parking spaces in front of the "public" charger were blocked. I pulled the CCS to see the length, but I did not find any way I could reach from either side so I had to abandon the test.