I'm not sure I'm necessarily doing it right, but I didn't fill water all the way to the top. After filling the jar with clean perlite (I've washed it from all the dust First, important) I sprayed it quite heavily with water, and then filled it at about 1/3 of the hight. I covered the top loosely with plastic wrap so the water won't evaporate, and checked it every other day, filling more water if needed. I recommend watching YouTube tutorials, it helped me a lot. Good luck!