Once your first Free Practice or Qualifying session has begun, you may leave the pits whenever you choose (providing you have the laps remaining for you in qualifying) via the Driver Menu. By clicking the Leave Garage button, after choosing an appropriate fuel load and tyre, you are signalling your intent to your engineers to leave the pits and go onto the track. When you exit the Driver Menu and advance to the next minute of the session, you will leave the pits and go out on track to record your first timed laps.
In Free Practice the primary aim is to maximise the setup of your car in the three main areas - wing angles (or fairings for bikes), suspension settings and gear ratios.
Whenever you leave your garage in the Free Practice session, you will be prompted as to which aspect of the car (or bike) you wish to improve, with the current setup percentage given for each. You may only change the area of the car you are working on by returning to your garage first, though you will still achieve minor improvements in the areas not selected while you run out on track. Over the 90 minutes of the practice session you must plan the most effective way to achieve the best overall setup, bearing in mind that a red flag may scupper your programme.
Your setup will improve in accordance with how high your pace and aggression sliders are, however pushing harder will increase the risk of you suffering damage that takes time to repair or even forcing you to miss the rest of the session completely, compromising your race weekend.
In order to determine which aspects of setup to focus on you will need to consider the characteristics of your car as well as those of the circuit. If your car is strong aerodynamically and if the circuit features a number of high speed corners, you will need good wing settings. If your car has good mechanical grip on a track with low speed corners, you should look to work on suspension settings. For a car with a powerful engine on a track with high top speeds you should prioritise gear ratios. Each parameter gives additional bonuses as outlined in the game.