1. Switch off the tablet by holding the Power button.
2. Second, press and hold together Volume Up + Power button for a few seconds.
3. Device should vibrate. When it does, releass the Volume Down and press Volume Up key.
4. You can release held keys after the Boot Mode appears.
5. There should be a menu on screen now. Select Fastboot by using Volume Up to scroll and Volume Down to confirm.
6. Congrats, you should be in Fastboot Mode menu now.