The video shows how to compare two Excel files /sheets for differences in a number of ways:
Via formulas and conditional formatting
By using special addins
View files side by side

For more information on how to compare 2 Excel sheets, please see:
https://www.ablebits.com/officeaddin...

To compare 2 different workbooks rather than sheets, try the tool from this tutorial:
https://www.ablebits.com/docs/compare...