After opening Crazyracing Kartrider, it'll check for game and GameGuard updates. After it updates, (or finds that there are no updates) a log in screen will appear. Log in. If you don't have an account, sign on on the Nexon website. After you log in, the game will open. If it's your first time playing, you'll have to first make a character. Also, you'll have to get your Beginner's License by passing a few basic tests. These introduce you to the controls of the game.
After getting a license, you're ready to race! Enter the multiplayer room and join a race by clicking one or using one of the random race buttons at the top.
Before the race begins, everyone has to be ready. (except the leader) In the case of team races, both teams also need to have the same number of people. Once everyone is ready and both teams have the same number of racers, the leader can press start to start the race.
In the race, you control the kart with the same controls you learned in the License test. For a refresher, see Controls. In the beginning of the race, press Up just as the word "Start" appears for a short speed boost. There are various objects on-screen you should be familiar with: