Data from LW compared to TW formula

Hello all, I have arrived here once again.

I do reports at work where I compare the last weeks data to this weeks.

The following is:
This week - Last weeks report C3:C5
Last Week Report - Sheet2!C3:C10)


Example:
I want:
Excel to find Employee Number for column B3, match the name with the employee number. Afterward, I want it to look in Sheet 2 for the previous weeks data, I want it to determine what the difference between last weeks numbers and this weeks numbers are.

Last weeks scan data - Sheet2!C3:C10)

John (349587)
Week 1: 12.4
Week 2: 34.2
Difference: 21.8

This is all part of making it an automatic like system so we can focus on the bigger tasks at hand.

Much appreciated, I thank you folks in advance!

Please note:
Employee Numbers, and names were chosen randomly and are not sensitive information.