Start off entering your investment sale the same way as if you sold stock and got a 1099-B. The second screen will ask you if you got a 1099-B. Click No, and continue through the screens to enter the information about the sale. It will be shown on your tax return as a sale that was not reported on Form 1099-B.
But why did you not get a 1099-B? Did you sell something that a 1099-B is not normally issued for, or did you sell investments through a broker or financial institution that should have sent you a 1099-B? If you should have gotten a 1099-B but didn't receive it, contact the financial institution and ask for a duplicate copy of the 1099-B or equivalent statement.
