Rather than replace the mesh within the default “MyCharacter”, it might be better to use the vehicle blueprint as the default character. I haven’t downloaded the racing game example, but I can give you the basic steps referring to the Vehicle Starter Game.
- Go to Edit->Project Settings
- Click “Maps & Modes” on the left and expand “Selected GameMode” on the right
- Next to “Default Pawn Class” choose the vehicle blueprint (Sedan) instead of “MyCharacter”
The vehicle expects MoveForward input whereas the Side Scroller expects MoveRight. So:
- Edit the Sedan Blueprint
- Delete the “InputAxis MoveForward” node
- Wire the “InputAxis MoveRight” node into “Set Throttle Input”
After you do that and compile, you should be able to play and move the vehicle. However, the Sedan is set to drive along its X-axis while the default Scroller plays along the Y-axis. Simply rotate the “Player Start” 90° whichever way works for you around the Z-axis. Finally, you’ll need to adjust the Spring-Arm camera on the Sedan Blueprint Components tab so that the camera views from the side instead of the rear. Rotate it 90° and the camera should follow. Also, under SpringArm Details, uncheck “Do Collision Test”. On the Camera Details, uncheck “Use Controller View Rotation”.
That should be enough to get you started at least. Have fun!