Generating formulas into specific cells, based on various formulas

Hello, I am trying to create a spreadsheet for financial analysis. Please see attachment for the example document.

End result, I want a Macro template to generate formulas based on various criteria. I want to be able to tweak this macro to suit my needs, and understand how it works, so explanations on important lines would be very helpful.
There are 3 sheets: Main, Cof and Dates. Dates sheet is used for a macro to generate dates which appear on top of Cof and Main sheets. Start date is the date when historical financial data is available, End date is the last date when its available (after this date data is forecasted) and last forecast year is what it says it is. Based on this dates are generated to fit my needs.

Historical data will be enter into Main sheet, up until the end date. I want a macro which would insert formulas on Cof sheet, based upon which growth coefficients would be calculated (say, Main! C5 is 1000, D5 is 1200, then I run the macro and formula in Cof! F3 is inserted, to return 5%.).

Then, on Cof!, after End date, coefficients will be inserted by hand, and based on them I want Main! to generate forecasts into the future, until last forecast date. Finally, the Main! Column A, the item number is important because formulas will only be generated in non-absolute item number rows. So, 2.1. 2.2. but not 2.

As I mentioned, ideally I want a macro template with explanations so that I could write the exact formulas and criteria and be able to tweak it in case i need to change anything, or need a similar macro for a similar problem.

Thank you.