VBA or Macro to Copy/Paste uniques value between 2 worksheets

Hey there-

I've been searching around and found bits and pieces of what I need to do but can't quite put it together the way I want it to work. Here's what I'm trying to accomplish:

At work I manage a base of accounts that fluctuates every month. I’d like to have Sheet1 contain a master list of accounts I manage and have subsequent worksheets contain the monthly updates of my accounts (paste an exported report into the worksheet each month). Then I’d like to ID the accounts that are in the monthly update but not in Sheet1 then copy/paste the whole row of the new account into the first blank row in Sheet1.

The columns I'm working with are as follows:

A: Parent
B: Child
C: Customer Name

We would identify the new account by looking at Column B: "Child" in Sheet1 and Sheet2. If the number in Column B in Sheet2 (the monthly update) does not appear in Column B of Sheet1, I need to copy the whole row from Sheet2 and paste to the first empty row in Sheet1.

I've attached a workbook that's a much simplified version. Thanks in advance!