RaceTrace comes populated with some sample data and tracks so you can get acquainted with the app before going to the track. You can create your own tracks in RaceTrace; you are not limited to the sample tracks. When you're comfortable using the app and have recorded data of your own, feel free to delete the sample data.
When you launch RaceTrace, it selects the Current Track based on your location.
To select a different track, tap the Change Track button or the track map/name. Choose from the list of existing tracks or tap the '+' button to create a new one. If you're at the track and in a hurry, just tap Start Session and start driving. You can set up the track later.
Set the start/finish line when you create a new track so RaceTrace can split your sessions into laps.
On the Home Screen, tap Start Session and begin driving. Data will be recorded immediately, but won't be considered part of a lap until you cross the start/finish line.
Tap End Session when you're off the track. The Session Data lap list will be shown with the session you just completed at the top. Select up to four laps in the lap list and tap Graph to display a speed vs. distance graph.
Pinch and scroll to manipulate the graph. The orange reference line on the graph corresponds to the orange line on the track. Those are the same points in time. The speeds at the bottom correspond to the orange lines.