I had read reviews where it was difficulty to validate the voucher. I did not have that problem. I arrived via the Amsterdam Centraal Station. I showed my digital receipt at the ticket info office and they processed it very quickly. I was given a card and map and voila, I was on my way. Card was easy to use from there. Amsterdam has great public transportation routes within the city and I found it easy to also get to the airport via the sprinter train I took.

Picked up from the greyish ticket machine by the platform 1 and 2 escalator. The greyish machine is next to the yellow ticket machine. You can’t miss it it says public transport ticket on it. Scanned GYG barcode, got my tickets in minutes and got on the train to Amsterdam Central in few mins from platform 2 Impressed with this seamless no stress service

Forget about the instructions to find the NS desk. Go through the station, out the far side to where the tram terminus is. Look out for a small white building across the road called GVB /tourist information. There you will eventually find a helpful person who will convert your voucher into a travel card. It took a lit of searching ad none of the help desk people had any idea..... once we managed it, we had a great time and the grand are excellent.