You have two Options to get this Achievement / Trophy.
1) automatically crafting with Healing Syringes.
Harvest 2 Green leaves and Ajay crafting automatically the Healing Syringe. With the Skill Harvester you harvest two leaves instead of one from a Plant.
2) manually crafting with a unlocked Skill.
In the Elephant Skilltree are 4 Syringe Skills. Unlock one of them for manually crafting. After you unlock a Skill, use your Wheel (hold
then
) to craft the Syringes.
Note: If you have the Material for a (unlocked) Syringe, you dont need to craft the Syringe, you can use directly the Syringe. The Game crafting the Syringe automatically. (maybe a Bug or Glitch)