Bahnhofstrasse 18, 8580 Amriswil; above the Coop supermarket.
There are sufficient parking spaces in the blue zone and behind Coop (the first hour is free); the Coop underground car park is only accessible during Coop opening hours. Approx. 5 mins. walk from Amriswil train station.
The entrance is on the bottom left in the picture below.