You may decide to borrow money to finance your fencing business, either by way of an overdraft or a loan.
You will have to pay interest on any money borrowed and there will also be bank charges due on the operation of your business bank account. Interest and charges are normally debited from your bank account every quarter - your bank will be able to help you estimate the amounts that will be due.
If you accept payment by credit card, you will need a 'merchant account' and you'll have to pay monthly credit card charges. Enter these in the cash flow under Bank/finance charges and interest.
Smartphone apps are now available to enable trades-people like fencing specialists to accept card payments when they're out and about.