Scenario Analysis on Google Sheets

I have the cash flow model and everything already built out as part of my budget. What I am trying to do is create a table where I can easily see lowest month of cash based on different revenue assumptions for next year. I could do this manually but it would be static and just capture a moment in time. I want it to update automatically as I update other aspects of my budget. For instance, if I change my personnel expense, I want to be able to look at the table and see the effect across various assumptions of cash flow. 

What is the best way to do this? Really appreciate the help!