Default PIPO M6 Pro soft navigation keys

Hi i have just bought a PIPO M6pro tablet

After about 10mins on it i pressed the downwards arrows on the bottom left and all the soft navigation keys dissapeared
I cant find any way to get them back? i dont want to have to reset the tablet each time i press it

Also if you do know of a way to restore them is there a way to turn off those arrows as my kids are bound to press it

Thanks