How do you know there is a loss, Balance Sheet cannot indicate such. It is an instantaneus picture of assets and liabilities on a certain date and even if you have more liabilities than assets (a sign of insplvency) it in no way indicates profitability or lack thereof. Enter everything from balance sheet as is and let the amounts all hit OBE. You would not post profit doing this so you do not post loss either. And the balance sheet won't indicate either one. Posting to retained earnings only is performed on first day of new tax year
If you are entering starting balances in balance sheet accounts, you would enter it as offset to what applies. If you know Equity, such as Retained earnings, is the offset, yes, put it there by the initial entry you make. Don't use Opening Balance Equity if you already know that this is "real" equity. OBE needs to be zero once the file is set up, and then it is never used again.
I know there is a loss because on the Balance Sheet I was given, at the very bottom, it states "Net Income" and shows (for example) -$50,000...Can I take that number and reduce the capital contribution to create a new opening balance for Capital Contribution?
You are confusing how to read the reports; let's examine what this really means: "because on the Balance Sheet I was given, at the very bottom, it states "Net Income" and shows (for example) -$50,000..."
That is Equity, not Loss. That Net Income value is coming from the bottom of the P&L = operations in this fiscal year have ended negative. However, Equity also has more components; at a minimum, you should also see Equity named, for instance, Retained Earnings or Unrestricted Net Assets or perhaps Fund Balances. You need to look at Total Equity, not the Net Income line.
"Can I take that number and reduce the capital contribution to create a new opening balance for Capital Contribution?"
No; it is part of the Trial Balance data. There is no Actual Entry named "net income" because that is the Math of all income and expense activities you need to enter. And Equity is the result of all other info; there is no entry that is Just Equity (or any other single value). Equity is synonymous with Net Assets, because this is "the accounting equation" that is always used:
Assets = Liability + Equity
Now, reverse it:
Equity = Assets minus Liability
That means, as you make your entries, you are Causing Equity to go up or down, like this:
Make deposit to the bank = Assets and Equity go up, as "make deposit for funds on hand as of the previous year end" is posted against Equity.
Write Checks = reducing Asset (bank) and increasing Expense (making net income negative, which is part of Equity), so Asset went down and Equity went down, because you Spent some of the asset on hand.
And let's examine buying inventory: Banking (asset) goes down and Inventory asset goes up = no change in Equity. What you had on hand as Money, is still on hand as Stuff. So, when you start a QB data file, your trial balance would have a generic Other Asset value, that is offset as part of Equity on hand. Then, you use Adjust inventory, to populate what is on hand by cost and quantity, because that is where the Asset value is coming from. In other words, Generic Other Asset would then go to 0, and Inventory Asset would now reflect what is on hand, because that is where the Value exists by products on hand.
Example: For the final date of the 2017 fiscal year, I see Net Income -$50,000 and Retained Earnings is $150,000. On the first date of the new Fiscal year, you don't see Net Income any more (as long as you have no activity on the first date), because the Math of Net Income rolled into Retained Earnings. That means the Retained Earnings is now $100,000.
You don't post Loss. You post Values. The reporting shows gain or loss.