Transfer Data between sheets

[ryanb4614]

Hello. This may be confusing so I have made an attachment for everyone to view.
Basically I get a product spreadsheet that has thousands of products on it from my distributor. I also get a spreadsheet with my category names and id numbers. I have made a custom spreadsheet with the distributors default categories are for each product and then in the next column I put what my store will have the categories as. What I need to be able to do is transfer the id numbers to the product spreadsheet and replace the distributors category name with my category id number.