To start adding and removing beers to your cellar, open the Beer Manager. This is done by clicking on the "Open Beer Manager" bar on the Cellar sheet.
When adding a beer to your cellar (or starting a review), you have the option to type in the information yourself, or to paste in the beer's Profile page from BeerAdvocate.com. These pages follow the format: "http://beeradvocate.com/beer/profile/..." Paste in the link, hit Tab, and the details will be automatically populated.
Brewery, Beer name, Style, % Alcohol, Format, Year/Batch, and Count are all required fields. However, if you are adding additional bottles to an existing beer in your cellar, then only enough information to match a unique record is needed. For example, say I have 1 bottle of 2010 New Glarus Belgian Red in my cellar, but just bought 2 more. Since I only have 1 beer named "Belgian Red" in my cellar, all I have to do is type "Belgian Red" into the Beer Name and "2" into the Count. However if I had a bottle of 2009 and 2010 in my Cellar, then I would need to add "2010" to the Year/Batch to identify which year I am adding bottles to. The same goes for Removing beer from the Cellar.