Though you stated you figured it out, I wanted to put the steps that I used for a year long, month by month balance sheet comparison so others could use this as a resource. I figured it out myself, but I came to this thread first trying to expedite my process.

Once you are on the balance sheet I selected "custom" for my dates. I clicked Customize Report, set my dates from 01/31/XXXX to 12/31/XXXX. I also selected display columns by month.