Look at draft 1040 before filling...how do I do that?

Please see the screenshot I added.

To view your 1040 form, follow these steps, see the screenshot below:

1. Sign in (continue) your online return, if you're not already signed in.
2. Select My Account near the top of your screen, and then Tools from the drop-down menu.
3. Under Other helpful links... click View Tax Summary.
4. Select Preview my 1040 near the top of your screen.
5. Click Back near the top of your screen to exit the preview screen.

To view all forms, schedules, and worksheets in your return:

1. From the My Account drop-down at the top, select Print Center.
2. In the pop-up, click the first option (Print, save, or preview this year's return). If you haven't paid or registered yet, you'll be prompted to do so before you can view your full return.