How Do I enable and disable TalkBack on my Samsung Galaxy Tab S?

Accessibility Service — TalkBack

The TalkBack feature is designed to assist users who have poor or no vision. TalkBack will read aloud the menu location you are in and it can also read aloud selected on-screen options. When the feature is turned on touch the screen with two fingers to navigate or select an item. To turn on TalkBack, from the Home screen touch Apps  > Settings  > Accessibility  . (Depending on your operating system settings you may need to touch Apps > Settings > My Device > Accessibility instead.)

Turning on TalkBack

1. Touch TalkBack and then touch the slider  to turn TalkBack on  .
2. Touch OK to continue and allow TalkBack permissions to the device. Touch OK to turn TalkBack on and turn off features that cannot be turned on while TalkBack is on.
   
3. A tutorial will be displayed (touch is turned off while the tutorial is speaking). With two fingers touch Exit to quit the tutorial or touch Next > Finish to complete the tutorial. 
   
4. If you would like to download a high-quality voice file for English touch OK with two fingers and then follow the on-screen prompts. Touch Do not show again to bypass this message in the future or touch Cancel to continue without downloading.
   Note: A Samsung account is required to download the voice file and we recommend that you are connected to a wireless network.

Turning off TalkBack

1. With two fingers swipe from the top of the screen to the bottom to access the Notification Panel. 
   
2. With two fingers touch TalkBack has been turned on.
3. Scroll down using two fingers slightly spread apart and with two fingers touch TalkBack.
   
4. With two fingers touch the slider  to turn TalkBack off   and then touch OK with two fingers to stop TalkBack.