There’s no need to buy train, tram or bus tickets anymore! You can simply tap in and out with your contactless credit card or phone wallet!
In the airport, you must CHECK IN before getting on the train. You can do that on these small totems in the lobby:

Make sure to ALWAYS check in when you get onboard, and check out when you’re leaving. You should hear a single beep when you check IN, and two beeps when you check OUT.
When moving between trains and metros in some stations (eg Amsterdam Amstel), you might have to tap out from the train and in to the metro. Sometimes these have different turnstiles as you move around the station, and sometimes when both Metro and Train move on the same physical platform, you have a small switchover (overstappen in Dutch) to do that.
Example transfer totems

**Yellow means train, Red means metro**

These red stickers mean you can’t get in from here, and the arrow points to where to go.

If you have an European IBAN, you can request in advance a “Personal OV Card” with a Flex subscription, which allows you to take public bikes on any train station for 4.55 EUR / day.
Otherwise, the easiest experience is probably Donkey Republic. There’s several dock spots around the centre you can pick one up via the app.
24/7 Easy Bike Rental in Amsterdam » Get the Donkey app here
⚠️ MAKE SURE YOU LOCK YOUR BIKE AT ALL TIMES! Bike theft is super common, and your bike WILL be stolen if you leave it unlocked. Always lock both wheel lock AND chain it to your parking space.
Taking your bike on the Train or Metro is allowed, but only outside rush hour (7~9am and 4~6:30pm on workdays). You NEED a supplement ticket (2.20 EUR for the metro, 7.50 EUR for the train).