There is a train station in Kundl.
Only slow trains stop in Kundl. You can use IC, EC and ICE trains anyway.
These trains stop in Woergl, which is about 7km from Kundl.
When arriving in Woergl you can change to a slow train for one more stop. (Direction: Innsbruck)
Once you are in Kundl (blue flag) you can use this map to find the festival hall (red flag):