VLookup in Excel for matches

Add users to new sheet (sheet2)
Sort Sheet2 A to Z

 Create New column on sheet 1 at far left (In front of A)

click on cell that lines up with the cell I need to start in that avoids headers

type in the cell the Function VLOOKUP

=VLOOKUP(Cell you want to look up, Cell range you want to look in, 1, FALSE)

   EX =VLOOKUP(C4,Sheet2!A1:A23,1,FALSE)

Before you copy to the next row and beyond, highlight the Cell range in formula bar, (in the above formula is Sheet2!A1:A23) you want to look in, then hit F4.

FINAL RESULT
=VLOOKUP(C4,Sheet2!$A$1:$A$23,1,FALSE)

After you press F4, click "enter" for the first cell to go back to what it should look like.

Copy down column A and click enter (right click to get the copy)

Sort Column A to Z, below the headers

Delete all #N/A rows