The instructions for using the Interapothek Menstrual Cup Size L are as follows:

1. Before using it for the first time, sterilize the menstrual cup by immersing it in boiling water for 5-10 minutes.
2. Wash your hands thoroughly before handling the menstrual cup.
3. Fold the menstrual cup into a "C" or "U" shape to make it easier to insert.
4. Adopt a comfortable position, such as sitting on the toilet or standing with one leg raised.
5. Relax your vaginal muscles and insert the menstrual cup into the vaginal opening, making sure it is fully unfolded.
6. The menstrual cup will stay in place thanks to the suction it creates. If you feel it's not positioned correctly, you can gently rotate it or push it in a little further.
7. To remove it, gently pull on the stem of the menstrual cup until you can grasp the base. Gently squeeze the base to release the seal and remove the menstrual cup.
8. Empty the contents of the menstrual cup into the toilet and wash it with warm water and neutral soap before reinserting it.
9. After each menstrual cycle, sterilize the menstrual cup again before storing it for next use.

Remember to read the manufacturer's instructions and consult a healthcare professional if you have any questions or concerns about using a menstrual cup.