How exactly do I solve the mortgage payable account to find total credited cash?

How exactly do I solve the mortgage payable account to find total credited cash? Frevert purchased a new piece of equipment to be used in its new facility. The $370,000 piece of equipment was purchased with a $50,000 down payment and with cash received through the issuance of a $320,000, 8%, 3-year mortgage note payable issued on October 1, 2014. The terms provide for quarterly installment payments of $30,259 on December 31, March 31, June 30, and September 30. Prepare an installment payments schedule for the first five payments of the notes payable. (Round answers to 0 decimal places, e.g. 125.) Prepare the journal entry related to the notes payable for December 31, 2014. (Round answers to 0 decimal places, e.g. 125. Credit account titles are automatically indented when amount is entered. Do not indent manually.)