This chapter of the guide to Dragon Ball Z: Kakarot has a walkthrough for Teachings for Tomorrow side quest.
Time frame: From Majin Buu Reborn - Episode 8: Finale to No time limit
Reward: 256,465 EXP, 15x D Medal, Super Awesome Book for Grown-Ups
Where to start: Great West Desert Area, as Gohan.
To start this mission, you need to go to Aloe Outcrop. Nam is waiting for you there - he has a new substory for you.
After talking to the merchant, you have to go to the farmer - he will tell you where to go next.
Fly to the city center and join the race. Reach 5 checkpoints to complete the mission and get rewards.