worksheetA = contains some manual entry plus data from monthly file
(worksheetB)
worksheetB = monthly file that gets updated from another system

worksheetC = contains parameters of the search
criteria1 = column C, D, E (primary region secondary region, tertiary
region)
criteria2 = column H, I, J (status, category, type)

worksheetD = contains count from worksheetA
column A = countA (region)
column B = countB (rest)

I need to do the following:
1) compare worksheetA and worksheetB using id_number.
if id_number on B does not exist on A, then add it on the last empty cell on
A
if id_number on B exists on A, compare if column M and N. If there is a
change, highlight it in red.

2) after the above compare, I need to revise the count on worksheetD (column
A and B) based on criteria on worksheetC

I just need a sample code to get me started. Many thanks for everybody's
time.
-Bob