Currently, you there is nothing to directly interact with in Visual Studio. There is another extension, automark*, which can read the git repository and generate a time-ordered diff for you. You could also use an existing git tool to see and interact with the history. Long-term, there are plans to merge the functionality.
A made a fresh project in visual studio 2013 and based on the description
"autogit will automatically commit a version of a file to a local git repository everytime a change is saved in a text or code editor. The git repository is located in $(SOLUTION)\.HistoryData\LocalHistory"
I would expect autogit to make the .HistoryFolder and start commiting things every time I save but this is no the case.
I don't know how to make this work and I can't find any directions anywhere