Here is another side story of Dragon Ball Z Kakarot which will ask you to find components that are sometimes quite difficult to find, such as the Meaty River Snail, high quality Herbs and especially the Golden Gazelle Antler which will be the main obstacle. This quest will be entrusted to you by Mr. Popo.
Animorphaline Accident
To help Master Karin make mushroom tea, you will need all 3 ingredients. The first one, herbs, are in the West Zone, in different positions. Here they are on the map. They're on the ground, usually under trees. They are displayed in red with Ki vision. Run around the area to scoop them up.
The Meaty River Snail is easy to find, you will have to dive in the large lake in the center of the Northern Mountain Zone. Look for shiny turquoise balls on the bottom of the lake near the algae.
The most difficult element to find is the Golden Gazelle Antler, you can get it in the Central Plains Zone, a little north of your starting point. You should see an NPC pointing out the position of the Golden Gazelle Antler in his text bubble. Now all you have to do is hunt the many gazelles nearby, aiming for the golden specimen first. The chances of getting the horn are low, so you will probably have to move away several times for the gazelles to reappear, and start hunting them again.