Red onion cut into half rings, garlic press, mix everything.
For marinade type a glass of hot (but not boiling water, and then the onion is cooked) water, add salt, sugar and vinegar. I used wine, but given the ratio of water and vinegar, I assume that the dining room can be taken in the same volume.
Carefully stir and fill in the form with onion-garlic, the water should cover them completely, if not enough-just add more hot water.
Close the lid, leave to marinate for an hour.