This polka by Helmut Freydl (Die Mooskirchner) is a popular instrumental among Oberkrainer groups in German speaking countries.

Preview:

‘Learn to play’ includes:

📝 Sheet music pdf (F)
🎼 Accompaniment playback mp3 (F)
📹 Slow tutorial video (F)

More options:

My arrangement for accordion
Legendary ‘Die Mooskirchner’ from Austria