Bring an empty water bottle that you can fill up once you get through security.
"A reusable water bottle is clutch for travel. The air in planes is dry, so you'll need to work extra hard to stay hydrated. That means means those tiny bottles of water you get on board won't cut it. If you're flying internationally, this is even more important because dehydration can actually worsen jet lag.
Bring a water bottle, fill it up once you get through security, and put it in your personal item so you can access it and drink plenty during the flight."
Yeah, some are only 10kg!
There is no step 2.
Enjoy your flight.