On your Apple TV®’s Home screen, go to Settings.
Step 2:
Select iTunes Store.
Step 3:
Select Sign In.
Step 4:
On the iTunes Store Account screen, enter your Apple ID and select Submit.
Step 5:
Enter your Password then select Submit.
NOTE: The Remember Password? screen will appear. Depending on your preference, select Yes or No.
It will try to access iTunes Store.
Once this is done, you will be prompted back to the iTunes Store screen and it will now show the Sign Out status and your Apple ID.
You can now play and enjoy the different media contents from the iTunes Store®.