You can refer to Wardee's instructions for basic first and second ferment. What follows is a similar process, but mine is tweaked to make it work for us. Everyone's water kefir is different!
The major difference is that I do my second ferment in Grolsch style bottles for even more fizz. (Wardee's Lacto-Fermentation eCourse has bottling instructions and videos, too.)
The first ferment (I do half gallon batches) is approximately 48 hours at room temperature.
Evenly divide between two 1 liter Grolsch style bottles; filling just to the shoulder of the bottle.
Grapefruit Water Kefir https://traditionalcookingschool.com/food-preparation/recipes/water-kefir-granita/?utm_campaign=autoblog&utm_source=blog&utm_medium=bloglink&utm_content=Water+Kefir+Granita