I previously chose to turn off the automatic display of the Hints screen. How can I turn it back on?

If you previously disabled the automatic display of the Hints screen and then later decide that you want to re-enable it, you can do so using the Settings screen.  On your iPad or iPhone, open the Splashtop Whiteboard screen which lists all computers that have been added, then tap the "gear" button  near the upper right of the screen to open the Settings screen.   Set the Show hints every time field to ON.