Where do I input realized gains or losses that are not reported on 1099B

To enter an investment sale other than from a brokerage account (1099-B), follow the steps below.

Click on Federal Taxes (Personal using Home and Business)
Click on Wages and Income (Personal Income using Home and Business)
Click on I'll choose what I work on (if shown)
Under Investment Income
On Stocks, Cryptocurrency, Mutual Funds, Bonds, Other, click the start or update button

Or enter investment sales in the Search box located in the upper right of the program screen. Click on Jump to investment sales

Using the desktop editions -

On the next screen click on Yes
On the next screen click on Skip import
On the next screen, select Other and continue

Using the online editions -

On the next screen click on Yes
On the next screen, click on Enter a different way
On the next screen, click on Other and continue