You cannot reliably make true water kefir grains from scratch at home
Obtain live water kefir grains from a trusted source
Dissolve sugar in non-chlorinated water
Add the grains to the sugar water
Add a small amount of mineral source such as dried fruit, molasses, or mineral drops
Cover loosely and ferment at room temperature
Strain the grains after fermentation
Repeat the process with fresh sugar water
Feed and reuse the grains regularly to keep them active
Avoid heat, chlorine, and metal contact for long periods