Macro for Drum Inventory

Hi, I would like to create a drum inventory system using macro. But I have no idea on how to create macro.
I have
i. 2 types of product for different
ii. Different customers using different type of drums
iii. Each drum type is further divided into new & old drums

I would like
i. When I key in products filled for customers it will deduct the empty drums and added into product stock level
ii. When I key in drums shipped to customers, it will deduct the product stock
iii. When I key in receives empty drums from customers it will be added into recycled empty drums
iv. When I key in new drums, it will be added into new empty drums.

At the end of the month I would like to have a report on empty drums available, stock level for different customers, total products produced, total products shipped out and total recycle drums returned.

Thank you for your help!!!

Please provide an example workbook showing your input and desired outputs.