Accounting help with depreciation please?

In my accounting class, we're doing financial statements based on transactions in a game of Monopoly. Last lesson plan, she gave us all sorts of basic transactions, including the purchase of rental property. For this lesson plan, we have to do accruals and deferrals, and one of the things we have to account for is depreciation on our rentals.

However, the actual process of calculating depreciation isn't covered til two lesson plans til now so I'm a bit at a loss. I have the total spent on rentals, and she gave us a 20 year useful life for each. Am I correct in assuming I would total the amount spent on rental properties, then divide by 20, to get the annual depreciation from which I could figure out the monthly depreciation?

And, from there, in which accounts would I record it? I know at least part of it involves my Depreciation Expense account...