Deduct expenses incurred at locations from their Sales

Hello all,

I am using FA for my business. We have about 3 locations apart from the main store and we want every expenses incurred at locations to be deducted from the sales of the locations. how can I use FA to accomplish this.
Secondly, when creating unit of measurement, what is the function of the decimal places there?
thirdly, how do i remove some of the accounts that I do not need in the chart of accounts.
Moreso, I do I know the breakdown of the stock a particular customer in a location has purchased from that location.

thanks.

popsicles12