You can type "stock sales" (without the quotes, plural sales) in the Search box, then click the link that says "Jump to stock sales." It will ask you whether you got a 1099-B, and you can click No.
But why didn't you get a 1099-B? There might be something out of the ordinary about the sale that requires special handling.
I don't see the option to select no 1099-B.
When I go to the "investment sales summary" and click "Add more sales," I see:
I click Stocks & Bonds, then:
I click "I'll type it in myself", then:
At this point it assumes I have a 1099-B.