From the beginning it was conceived to be a military base for the German army - before and after the Olympics.
After the end of World War II it was used as a Soviet military base until 1992.
This explains the mixture of old German buildings and more recent Soviet buildings and the propaganda art work on the walls being also from Germans and from Soviets/Russians.
The Olympic Village is easily reached by regional train from Berlin to Elstal and a 2km walk. The Village is open every day from April to October. While you can walk around without a tour, I highly recommend paying the 5 Euros and getting access to the buildings and all the inside information from the knowledgeable tour guide.