help needed with macro for adding formulas

Hello,
This is my first time to use a forum and also I am not very good with macros/excel, so apologies if I make any mistakes or if none of this makes sense.

I need a macro that will add formulas to a speadsheet that contains rows of data.
The formulas contain absolute references and must start after every blank row of data.
I have attached a file that contains the data. This would normally not have any information in column M ( I have included this column so that you can see the formulas that I need added)
I never know how many rows of data I will get, the only thing I know is that there is one blank row between each data set and that the absolute reference must be from the first row in each data set.

Any pointers in the right direction would be much appreciated

That works perfectly. Thank you for your help.