@klabunde Between 9 a.m. and 3:30 p.m., you can only see the Anne Frank House if you've made a reservation in advance. These advance reservations are very hard to get. Exactly two months prior to the date of your visit, you need to go to their website. The tickets are released between 8 and 10 a.m. Amsterdam time, plan ahead for your time zone. It is possible to reserve a spot for a Museumkaart holder--even though you don't have your pass yet. Just scroll down through the options until you see the Museumkaart option. It will only cost you 50 cents to make your reservation. When you get to Amsterdam, do not buy your Museumkaart at Anne Frank House. Buy it at another site prior to your visit--preferably a place that's not busy such as the Royal Palace or the New Church on Dam Square.
If all the tickets are sold out for the dates you will be in Amsterdam, buy your pass in advance and try to go to the museum late in the day--say 7 p.m. Usually there isn't much of a line at that time and in summer the museum stays open until 10 p.m. Good luck and you'll love Amsterdam.