Samsung GALAXY-TAB-A user manual

Here's how you can manually reset your Samsung Galaxy Tab A:
IMPORTANT: Resetting your device will erase all of your personal data, settings and apps.
1. Backup the data on your device before starting the reset process. You can backup your data to your Google Account, Samsung account or directly to your computer.
2. Once your backup is complete, start by switching off your tablet completely.
3. After it's off, press and hold the Volume Up button, the Home button, and the Power button together until you see the Android on screen.
4. Using the Volume Down, scroll down to 'wipe data/factory reset' and press the Power button to select it.
5. Scroll down to 'Yes — delete all user data' with the Volume Down button and press Power to select it.
6. After the reset is complete, you'll see an option 'Reboot system now' , use the power button to select this option and your device will restart.
7. Now, your device is back to its factory condition. You can now restore your data from the backup you created earlier.
Note: The process can slightly vary for different models. Ensure you follow the correct steps for your specific Samsung model.

The Samsung Galaxy Tab A was first released in 2015, so as of 2021, it is around 6 years old.