You need to wait for a guided tour. Tours start on the hour until 4 pm.
We went on free museum day and had option of taking the tour or just walking through on our own. Not sure if that applies other times.
You can only walk around the very small outside entrance garden and around a corner to see the building from a couple of points of view. Not that much but nice architecture! Otherwise as Greg Zaric says.
Guided tours only and no photos inside.
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