Tell us about yourself!
Do the LEDs on the arduino turn on when you put in the batteries and turn it on? Are you using the same 18650 3.7 volt lithium batteries I did? are they fully charged?
Are you using the same script I posted?
Also, this is may be too obvious, but in the picture you posted, there are no batteries in it...
Can you be a little more specific about what isn't working? Is it driving off in a straight line and ignoring the track? Is it driving in circles? Is it not moving at all? Try printing some diagnostics to the serial monitor to see if each sensor is responding correctly
I uploaded the missing files, and for good measure, I uploaded a zip file containing all of the solidworks parts for the assembly. If you build one, let me know how it goes!