After you file

Yes, you can start from there to amend your 2017 return. Unfortunately, the IRS will not let you e-file the amended return.  You have to print and mail it.  

1. Click on Federal in the bar to the left 
2. Click on Other Tax Situations at the top
3. Scroll down to the bottom of the page to Other Tax Forms
4. You should see Amend a Return, click Start

I attached a screen shot of the next screen where you start.