In Settings
1.- We select Location and security
2.- We press on to configure blocking screen
3.- If we have an old pattern we introduce it, if we do not go to step 4
4.-Click on Pattern (it's more like the pin)
5.- We make a pattern on the screen and click on continue
6.- We confirm the pattern repeating it and we confirm again
When we turn off the screen (or turn off manually with a short press on the power button off) and want to re-activate will ask us to enter the pattern to unlock the terminal.
Note: The easiest way to recognize a pattern is by looking at the dirt on the screen