• After you complete the ekasana (one meal in one sitting during daylight), you do not eat or drink anything else for that day until the next daylight window begins.
• The next day, you begin another ekasana during daylight (usually after sunrise and before sunset), following your community’s rules (Digambar or Shwetambar) and your guru’s guidance.
• Water rules vary by tradition: some allow water only with the meal and none before or after, and many observers avoid water after sunset. In stricter practices, water may be restricted even more. Check with your local sangh for the exact rule you should follow.

To read more about how to perform Ekasana and related guidelines, you can read here and here