Enduro atari 2600

I want to do an Enduro Remake but dont know where to start. Enduro is a racing game from the Atari 2600. its track is similar to Pole Position. here is a website with some picture: http://8bitcity.blogspot.com/2013/10/enduro-atari-activision.html

I don't know much about the game but maybe you should first make the driving part first, like the physics and track and stuff.