Hi there! I can definitely help you with that. You can use the LEFT and FIND functions in Excel to remove all characters up to and including the first blank space from left to right, regardless of the length of the first name. Here's how:

1. Assuming your full names are in column A, create a new column next to it (column B) where you want to display the last names only.
2. In cell B1, enter the following formula:
   Formula:

   =RIGHT(A1,LEN(A1)-FIND(" ",A1)) 

3. Press Enter. This formula uses the FIND function to locate the position of the first blank space in cell A1, and then subtracts that position from the total length of the cell using the LEN function. The result is the number of characters in the last name. The RIGHT function then extracts that number of characters from the right side of cell A1, giving you the last name only.
4. Copy the formula down to the rest of the cells in column B by clicking and dragging the small square in the bottom right corner of cell B1 down to the last cell in the column.

That's it! Your new column should now display the last names only. Let me know if you have any questions or if there's anything else I can help you with.