Samsung Galaxy Tab 2 (10.1) Recovery Mode
How to Hard Reset Samsung Galaxy Tab 2 10.1 Android 4.0 Remove Password
How to Delete All Data in SAMSUNG T520 Galaxy TabPRO 10.1 WiFi - Factory Reset in Samsung
Hard Reset SAMSUNG T520 Galaxy TabPRO 10.1 WiFi - How to restore tablet
Hard Reset will erase all of your data
All described operations you are doing at your own risk.