This is a memorandum record. That is, it does not form part of the double-entry system. The Payables Ledger is a way to keep track of which suppliers you owe money to.
An account is kept for each supplier. Purchase/expense invoices from the supplier are Debited to their account (it is not a double-entry - it just mirrors the Dr entry to the main general ledger Payables Control account). Similarly, payments to the supplier are Credited to the account. The difference between the two sides is the amount you still owe that supplier at that point in time.
Later on, you will see how the reconciliation between the individual Payables Ledger accounts & the main Payables Control account in the General Ledger provide a check for errors.