3 Excel Spreadsheets

I have 3 Excel documents which are exports of data from a website and unfortunately there is a problem with them.

The first sheet is directly from the website without the category ID numbers
The second sheet is an updated version of the first sheet without the ID numbers
The third sheet is an export of the categories with ID numbers

What I need you to do is add the correct ID number to the updated category name and information

There are less than 5,000 categories

Thanks