Turn off the device completely

Press and hold the Volume Up, Home and Power keys at the same time.

When the logo "GALAXY Note 3" appears on the screen, release the Power key but continue to press and hold the Volume Up key and the Home key.

When the Android System Recovery menu appears, release the Volume Up and Home keys.

Use the Volume Up/Down keys for navigation in the menu and the Power key to select "'wipe data / factory reset".

In the next menu select "Yes -- erase all user data" and "reboot system now".