One of the most common ways to lock a Samsung Galaxy tablet is to apply an unlock pattern: The pattern must be traced exactly as it was created to unlock the device and get access to your apps and other tablet features.
Summon the Screen Lock window.
Choose Pattern.
If you’ve not yet set a pattern lock, you may see a tutorial describing the process; touch the Next button to skip over the dreary directions.
Trace an unlock pattern.
You can trace over the dots in any order, but you can trace over a dot only once. The pattern must cover at least four dots.
Touch the Continue button.
Redraw the pattern.
You need to prove to the doubtful tablet that you know the pattern.
Touch the Confirm button.
Type a PIN to back up the pattern lock in case you forget.
And the pattern lock is set.
To ensure that the pattern shows up, check that the Make Pattern Visible option is selected on the Lock Screen window. For even more security, you can deselect the option, but you have to be sure to remember how — and where — the pattern goes.
The unlock pattern can be as simple or as complex as you like.
Wash your hands! Smudge marks on the display can betray your pattern.