This game's home screen allows you to toggle several different options. You can toggle two sets of driving controls, the presence of a computer kart and the ability for car damage to be done. Since leaving all of these options on makes for the most convenient and fun driving experience, you will likely just want to hit the Continue button at the bottom of the screen.
You'll then be able to choose whether you want to race the Easy, Medium or Hard track. You can also customize how many laps you'll race by selecting the Laps blank and entering the number you want.
Once you make your selection, the race will be underway. Guide your kart around the track by using the arrow keys.