Dear Guest,
Thank you for your feedback.
Kindly note that the instructions of how to download the app and the audio tour are clearly stated at the end of the voucher that you receive from Viator.
Besides that, as mentioned in the application, If you had any issue while downloading the audio on your mobile, you could had also contact us by phone or email to resolve this problem immediately.
Always at your disposal.
Kind Regards,
Margarita Karavasileiadi