Declaring variables for use in formulae

[doesnotcode]

Hello! I had posted this question on Stack Overflow, but was told that it isn't the right place for such a question. I have two sheets in Excel, one with formulae calculating business costs, and another where I'm trying to calculate revenue projections based on those costs. Images: Costs Projections

I'm trying to set it up so that the blank rows in the Projection sheet are dynamically calculated using the formulae from the Costs sheet, based on 'Sales' and 'Markup' values input by the user.


I have also tried using Scenario Manager and Data Table options in Excel, but they didn't work. What is the simplest solution with / without scripts? Grateful for any advice on this.

 

[doesnotcode]

I realise this question may not be clear enough. Since I don't have edit permissions, here are further details:
The Costs sheet already has values for 'Sales' (D18) and 'Markup' (D26). What I'm trying to achieve is a formula that will automatically calculate the 'Variable Cost', 'Price', 'Revenue', and 'Profit' (E23, D27, E29, and E30, respectively, in the Costs sheet), based on values for 'Sales' and 'Markup' that a user inputs in the Projections sheet.