Opening balances for P&L accounts

I am transferring to Manager from another accounting package mid-year, therefore my P&L accounts will have opening balances. I can see how to enter opening balances for Balance Sheet accounts as this is covered in the guide, here:
http://www.manager.io/guides/miscellaneous/setting-up-opening-balances/

… but how do I set up opening balances for sales, wage expense, etc.?

You can enter the year-to-date income and expenses as a journal entry and post the net profit to the retained earnings account.

thanks Tony, I’ll do that.