bruno, the reset button is to perform a normal restart. I speak of a hard reset, which is what implies a loss of information.
To do this you should follow these steps:
Completely off the device.
Once the unit is turned off. Press and hold the "Back" button and the power button "press and hold both buttons simultaneously" for eight seconds.
When the Android icon and warning triangle appear, press the "back" button (silver button) once.
Android recovery screen appears. The "(Home) Home / Menu" buttons allow you to scroll up and down.
Click the Start (Home) / Menu button to scroll to "Factory Reset Wipe Data /" then press the "back"
On the next screen go to "self-erase all user data" Press "back" button.
Step onto the "reboot system now" option and press the "back" button.
Now you can access the tablet.
A greeting.