Setting up auto tab to next text entry box

I have read several posts where individuals have set up auto tab to go to the next TEB once the max number of characters are placed in the box.  However, I can't find any that actually explain how to do this.  I would like to auto tab to the next TEB.  I have 3 on one page.  They work correctly when I manually tab--it would just add convenience for the user.  Thank you.