Where/what exactly do I sign, and what do I include in my amended return?

I've got my 2017 1040X ready but a bunch of stuff printed out with it so I am not sure exactly what to sign and what to include in the envelope I'll be sending to the IRS, and the TurboTax instructions are not explicitly clear on this.

Here's what printed out:

1) 2-Page 1040X form, signature line at bottom of second page.

2) Entire 2017 1040 form, signature line at bottom of second page.

3) After the 2017 1040 form, there are two pages of additional information that mention 1040X.

Questions:

1) Which forms do I sign and include in what I am actually mailing to the IRS?

2) Which of these 3 items listed above do I include in the mail to the IRS?

Thank you so much!