Opening balance questions on setup of ERPNext

I am in the process of migrating my accounting to ERPNext from different accounting software. The problem I have is more of an accounting question than a problem with the software:
When I use the trial balance from the end of the fiscal year 2018 in my old software, it includes the profit for all previous years and it balances out. When I enter the same information into the ERPNext opening balance journal entry, however, I can’t find a way to include the previous years’ profit, so my accounts are off by that amount. Is there an account I need to create to enter that value?

@owen you should take a look at Period Closing Voucher.