How can I delete my Federal and start over i have not signed yet and I have a second w2 I need to calim for aprevios job

You don't have to start over, once you haven't filed yet you can add your additional W-2 by following these steps:

1. On the Tax Timeline menu at the top of the screen, select "Federal Taxes".
2. Select "Wages and Income" underneath on the second menu bar. 
3. Select "Edit/Add" next "Job (W-2)" to view a summary of all W-2's entered on the return.
4. On this screen, select the "+Add another W-2" button to add income.

after scanning last years returns it kept referring to last years returns and I got the impression that my return have been done wrong

If it is in regard to last year's return, you'd have to file an amended return.