This achievement is super easy to get and although worth 0GS, you have to get this achievement if you want to unlock another one (I forget the name but it will be worth 25GS)
Go to free play.
Click Select Car, then click on Rent car.
From there you will want to choose Ferrari 250 GTO 1962.
Click Select Track, you'll choose Sebring International Raceway. Then click the first track called Full Circuit.
It's completely up to yourself how many laps you do but it only requires one to unlock the achievement. If you want to change the number of laps, do this after you've picked your map.
Go to Game Options, Laps and then choose how many you want to do.