What is the difference between these two types of referencing and what do you have to do to achieve each?

I presume that relative referencing is the normal type of cell referencing when you type, for instance, =A1+B1 in cell C1 and then drag it down column C, this will give =A2+B2 etc.

Absolute referencing is where, no matter how far you drag the formula down, it always looks at the same cell.

to do this, add dollar signs before the reference you want to stick.

for instance, =A1+$B$1 dragged down will then give =A2+$B$1 etc...

Hope this helps

Paul