Please explain

Information related to Novak Co. is presented below. 1. On April 5, purchased merchandise on account from Kingbird Company for $31,400, terms 2/10, net/30, FOB shipping point. 2. On April 6, paid freight costs of $810 on merchandise purchased from Kingbird. 3. On April 7, purchased equipment on account for $31,000. 4. On April 8, returned $4,400 of merchandise to Kingbird Company. 5. On April 15, paid the amount due to Kingbird Company in full. Prepare the journal entries to record these transactions on the books of Novak Co. under a perpetual inventory system. (List all debit entries before credit entries. Credit account titles are automatically indented when amount is entered. Do not indent manually. If no entry is required, select "No Entry" for the account titles and enter O for the amounts.) Assume that Novak Co. paid the balance due to Kingbird Company on May 4 instead of April 15. Prepare the journal entry to record this payment. (List all debit entries before credit entries. Credit account titles are automatically indented when amount is entered. Do not indent manually. If no entry is required, select "No Entry" for the account titles and enter O for the amounts.)