When you amend a tax return, you are not literally making changes to the tax return that you already filed. An "amended return" is actually a separate form, Form 1040-X, that specifies what you want to change and recalculates your tax. You send the Form 1040-X to the IRS to make the changes.
You are correct that there is no communication between TurboTax and the IRS about amending your tax return. Nothing gets sent to the IRS until you send the Form 1040-X. Clicking the Amend button merely takes you to the place in TurboTax to start preparing Form 1040-X.
At the present time TurboTax does not support e-filing of Form 1040-X. The only way to send it to the IRS is for you to print it, sign it, and mail it. As one of the videos tells you, you have to attach the updated copies of any supporting forms or schedules that are changed.
Since you are using the CD/Download TurboTax software, before you start to amend your return, save a copy of your original filed tax return with a different file name. You will then have two identical copies of the file. Amend one copy, and keep the other copy unmodified for future reference, or in case you have to start the amended return over again.
