Steps on how to use TurboTax Easy Extension :

1. Click on the Federal Taxes tab
2. Click on the Other Tax Situations subtab
3. Scroll down to Other Tax Forms 
4. Select File An Extension

The important thing to remember about extensions is that they only extend your time to file the return.  If you owe money, then the IRS and states expect you to pay by the normal tax deadline -- there's no extension for paying. So if you're filing an extension and you believe you'll owe, then you'll want to mail a check to the IRS or state.  

On the other hand, If you normally receive a refund, and you don't anticipate any change, then you don't need to send payment.

In regard to your state return: Some states will piggyback off the federal extension, so there's no additional state form to file.  Other states require you to submit their own extension forms.  TurboTax will walk you thru the state extension as well as the federal process to ensure you follow the requirements of your state.

If you're curious about your particular state, here's a list of extension requirements by state: https://www.irs.com/articles/state-tax-extension-information