Button highlighting on tabstop

Question

Hi,
   I am designing a c# program in Visual Studio.  This program is a fitness tracker for persons with disabilities, specifically Down Syndrome.  All of the buttons within the program are accessed by means of a simplified keyboard consisting of the arrow buttons, tab button, and enter.  
   What I am looking to do is make it so that when you arrow over to a specific button, it will change color so that the user can tell exactly where they are within the program or rows of buttons.  I do not have the option to use a mouse but have seen the feature for mouseover which allows one to do what I am looking to do.
   The simplest solution would be better as we have a delivery date for this project of May 7th.
Thanks kindly,
John