In this video guide I will show you how to validate a total of 5 tracks in Track Builder mode. First go over to the track builder tab and select track builder. Select the first level Basement. Now just follow the instructions to get threw it to get the first achievement.
Now back out and select the next map Skatepark. Now all you need to do is choose course in the category menu. It will automatically select a start line. Now go select finish line under animated in the category menu.
Next press the start button and go to validate the track. You can choose to save or not save, then go to the next map. Keep going to the next map until you hit your 5th level and the achievement will pop.