How do you unlock Galaxy S5?

As a disclaimer, keep in mind that resetting the Samsung Galaxy S5 may delete most, if not all the files stored. Before performing this, make sure the device is fully charged.

Turn the phone off. Then, press the power button, volume up button, and home button all at the same time. Keep it depressed until you see the Android logo on the display. Using the volume controls, use the volume down button until you get to "wipe data/factory reset". Press the power button, then confirm by highlighting "Yes - delete all user data". Press the power button again. When you see the "reboot system now" option, use the power button to choose it. After it restarts, it should take you back to the phone setup screen.