We use an internal Google account to set up the tablets, in order to use your own account, you’ll need to disconnect the Flyability account, then add yours.
To do so, go to the tablet’s settings, on the left part, choose “Accounts”, select the Flyability account, then go to the menu called “more” on the top right of the screen, select “remove account”.
Then you can set your own account selecting “Add account”.