VBA Macros in Excel - VLOOKUP ad IF Statements

I am new to the VBA and I don't know how to reach the solution.

I have 2 sets of data in different worksheets but same workbook. I need to VLOOKUP column from sheet 1 in sheet 2 and (that is where it is becoming interesting) if there is no match in the lookup value (N/A) I need to copy that missing value from the sheet 1 in the end of the data in the sheet 2.

In practice, the data in sheet 1 is going to be periodically updated, and I need a macros that will check for those updates in sheet 1 compare them to what is in sheet 2 and update sheet 2 if necessary.

Thank you in advance to everyone who answers to this!