I just did a 5 hour and 8 hr layover in AMS, getting from the plane to the train takes about 15 minutes and then 15 mintues to the city.

You'll just have to wait for your bags. On the 8 hour we went to the Van Gogh Museam, walked around the shops and had lunch with plenty of time.

The 5 hours we shopped and had some coffee.

The ticket vending machines only take mastercard and you need to konw your PIN to use it. Otherwise you have to buy the tickets from the line. 6.2 euros plus the 50 cent charge for using the person to buy tickets for a same day return ticket per person.

I think all trains stop at centraal station that are heading towards amsterdam.

At Centraal station, there is a separate monitor that tells you each train that goes to the airport and run about every 5-10 minutes.

Enjoy!

PS I vote to stay there overnight