How to add excel formulas and pivot tables to multiple excel sheets that have already calculated data?

Hi yeah I messed up, ive been doing this assignment for a lecture where I had to analyze data and calculate them according to the specific questions I had been given but after doing so ive just come to the realization that I had to include visible excel formulas and pivot tables to show how I got to those calculations, since I am somewhat new to this i don’t know if there is a easier way to actually include these or will I have to do everything from scratch? Please help me out here and thank you in advance.

(I am on the latest version of excel or office 365 I guess?)