Journal entries are entered into the General Journal.
We move journal entries to T-accounts. T-accounts make each account and the balance easier to see.
The T-account balances are transferred down to ledgers with the transaction date. Note the carrying balance in the ledger.
The posting reference (PR) is like a bookmark. Once you've entered it, you know you've completed the step. The PR in the general journal is the account ledger number. The PR in the ledger is the general journal page number (for example, G1). You do this after every posting. You need to know where you left off.
The trial balance takes the ending balances of each ledger account and it must balance.