If you are planning to go, know that it is a very popular site and there are a few rules it helps to know in advance.  Tickets can only be purchased online, here. 

80% of the tickets are released exactly two months in advance at 12.00 hours. The remaining 20% are released on the website on the day itself at 9 AM.  People waiting until the release on the day are often disappointed.

You have to choose an exact time and there is only a window of 15 minutes, so you have to arrive on time or you won’t get in.

Photography is not permitted.

The visit takes a little over an hour.  There is also a half-hour pre-tour talk available for 5 EU. 

There is a small cafe overlooking the canal and a book shop.

A pleasant way to get there is by hop on hop off canal boat, tickets can be purchased online, here, or onsite at many ticket offices along the canal.