Dumdumdingdong be waiting for me to reconnect.
If you are installing from another Android device that's normal.
Dumdumdingdong How long should the flash process take
A couple minutes. The installer tells you what it is flashing, if it remains on one step for too long it's stuck, in this case something is wrong with the physical connection between your tablet and the device you are installing from. Do not interact with the tablet while it's being flashed.
Dumdumdingdong where and how do I lock the bootloader ?
Once the flashing process has completed your tablet will be back in fastboot. All that's left to do then is click the respective button on the web installer and confirm the action on the tablet, just like you did when you unlocked the bootloader.