https://www.klm.com/travel/us_en/prepare_for_travel/at_the_airport/connections/index.htm

http://www.schiphol.nl/WelcomeToSchiphol/TransferringAtSchiphol1/FrequentlyAskedQuestionsAboutTransferring.htm

Flagged for moderators to merge with the exhaustive existing threads in the Destination forums and KLM forums on this topic.