This page of the guide to Dragon Ball Z: Kakarot has a walkthrough for the Victimized Namekian side quest.
Time frame: From Evil Emperor Frieza - Episode 3: Hunt for the Dragon Balls - Episode 3: Hunt for the Dragon Balls
Reward: 7,903 EXP, D Medal, Master Korin Plush
Where to start: South-Eastern Islands, as Gohan.
Start this quest by talking to the Namekian child.
Your first task is to kill several opponents. They shouldn't be a challenge.
The second task is to collect four Namekian Fruits. You will find them under the trees. They have a distinct light purple color.
When you return to the quest giver, you will be attacked by opponents. You must defeat them.
The last part of the task is to reach and talk with Bulma. This will complete the mission.