Create desktop program (calculate earnings using 2 excel files: buys-sells)Very simple

i have to files in excel First file :Buys - Second file: Sells example: *Purchases (file 1) User1 - 100 dollars - 0.1 BTC User2 - 120 dollars - 0.1 BTC *Sales -(file 2) User 3 - i charged 200 dollars (less 10% comissions) = 180 dollars --- 0.15 BTC (plus transaction fee +0.0001)=0.1501 BTC (file 3) I NEED EXPORT AN EXCEL FILE what WILL CALCULATE EARNINGS LIKE THIS: User 3 : 100 dollars - 0.1 BTC - user1 + 60 dollars - 0.05 BTC - user2 ---------------------------------------------------- 160 dollars - 0.15 BTC i charge in total 180 dollars EARNINGS: 20 dollars -------in File 1 (BUYS) remains a balance of user 2: (THIS DATA WILL BE USE FOR NEXT SALE or if not more sales export a new file with new stock) user 2 - 60 dollars - 0.05 BTC i have excel files examples you can use and you can tell me if you want changes for improvements purposes. (3 files are related , open 3 at same time)