What do the blue cells mean?

The blue cells are for inputs. All models are designed to be fully flexible, thus they are fully linked. For example if you change a salary item in the 5 year projections the change will filter through the appropriate departments compensation, expenses, taxes and be reflected in the income statement as a different expense.

Note that if a cell has a black color it is a formula and if changed runs the risk of blowing up the entire model - meaning the dreaded #Ref errors appear. If that happens use the undo command.

How do check changes?

5 year projections - The best check if changes are being accepted is to look at the balance sheet and determine if it balances - there is a check that compares assets to liabilities& equity.