The documentation centre is situated in block 3 in the centre of the complex next to the former theatre.  The official address is since autumn 2018 Dritte Straße 4.
Some navigation apps have older names, Strandstrasse 74, then the best is to choose Dokumentationszentrum Prora as point of interest.

There is a parking in front of the building. The fees are not taken by us but by the owner of the plot.

The closest train station is Prora, a 1 km walk.