how do i review my return before filing?

Click on Tax Tools on the left side of the online program screen.  Then click on Print Center.  Then click on Print, save or preview this year's return. 

To preview only your 1040 form:

1. Select Tax Tools. 
2. Select Tools
3. select View Tax Summary in the pop-up, then 
4. Select Preview my 1040 in the left menu.