You can open additional boxes for the sale of securities as follows:
1. Under the Federal Taxes tab, on the Your Income page, select Stocks, Mutual funds, Bonds, Other.
2. Click Edit beside the broker's name.
3. On the page headed Here's all the sales reported by [broker], click Edit.
4. On the page headed Tell us about your [broker's] 1099-B, you will see Box 1a, etc. (This is also where you can enter the info by hand, either individual transactions or summaries for each sales category.)
Click the blue box, Guide me step-by-step to add more info. See the screenshot below.
If following these steps doesn't allow you to enter the information you need, please write back with a description of what needs to be entered.