Yes, you can definitely use Journal Entry so you can add your previous transactions at once, Reforminded.

A journal entry is a record of the business transactions that consist of the correct date, amounts to be debited and credited, description of the transaction, and a unique reference number. You'll have to make sure that you're using the correct accounts for your entries. Also, you can only open reports based on the JE that you've entered. To create a journal entry, you can follow these steps: 

1. Click + New.
2. Select Journal entry.
3. On the first line, select an account from the Account field. Depending on if you need to debit or credit the account, enter the amount in the correct column.
4. On the next line, select the other account you're moving money to or from. Depending on if you entered a debit or credit on the first line, enter the same amount in the opposite column.
5. Check the amounts - you should have the same amount in the Credit column on one line and the Debit column on the other. This means the accounts are in balance.
6. Enter information in the memo section so you know why you made the journal entry.
7. Click Save.

For your reference, you can also print multiple journal entries on one report.

Keep in touch if you need anything else about recording your transactions. I'll always be right here to help you.