Any help on this? I'll 'scale' it up for my own needs later.
At the moment I have a macro for each cell in the b column of section one
comparing to cells in b column of section two that uses lots of 'If', 'Then'
and 'ElseIf' fired by a worksheet change in section one. Coding to make this
work is huge, inefficient and prone to typo errors.

There are two sections on worksheet.
Section one range is A10:E20
Section two range is A30:E40

Can you explain how to use loops, variables and worksheet change to make the
following happen?
If there is a match between the values in the B column in both sections then
the values from from corresponding rows are are carried down.

Examples:

If the value in B11= value in B34 then A34 = A11, C34 = C11 and E34 = C11
If the value in B15= value in B30 then A30 = A15, C30 = C15 and E34= C15