A debt schedule is the complete list of what the business has borrowed.
What each line holds
The lender, the original amount, the current balance, the interest rate, the payment amount and frequency, the remaining term, and any security given.
Anything that has to be repaid belongs on it: term loans, equipment finance, vehicle finance, a credit line, merchant cash advances, and balances carried on a credit card.
Why it is kept as one list
The total monthly payment is the figure that matters, and it is the one most often not known. Borrowings are usually taken one at a time, years apart, and never added up.
That total is the input to debt service coverage, which is how a lender decides whether more can be afforded, and to the cash flow forecast, where the payments fall on known dates.
Payment is not cost
Only the interest portion of a payment is a cost. The principal is repayment of money already received and never appears on the profit and loss at all.
This is why a business can be profitable and still find debt payments unaffordable: most of the payment was never a cost, and profit never accounted for it. The split between the two changes over the life of the loan — see amortization.