Which formula to use - 2 workbooks, multiple criteria and result to look up

Hi All,

I am not new to excel, but I am surely no expert. I am struggling with an assignment and I would love to get some tips because I am not even sure what to search/google for.

I got two workbooks, on one, I have a customer order: SKUs - ID of the product, quantity ordered, quantity left to deliver (PICK), name of the product and so on.
Second workbook - Stock report, I have 4 different warehouses so it shows me where each SKU is available (It can be in 2-3 different locations at the same time) but I can only deliver from 2 of them, so the other two are not relevant, quantity available, product name etc.

I need to make an Excel showing which items are left to deliver from the customer order and see at which warehouse they are and how many are available.
I also saw that some SKUs from the customer order are not shown in the stock report at all - meaning they are not at all in the stock worksheet.

I am lost on how to combine these two workbooks and see fast and clearly the result I need.

Can someone please help me?