Daisy made this point earlier but the container for one of these plants should have holes in the bottom. You need to flush the soil, not just wet it. These plants enjoy it when the soil goes completely wet, then dries out almost all the way. That's what you should aim for. They will gradually waste away if they receive a few drops now and then. It's not so much that they do not like a lot of water (they love it actually), it just has to be spaced out over wide enough intervals that the soil can go dry in between. It's more a matter of timing than quantity.
The rocks on the bottom for drainage are not doing anything without drainage holes, and in the end they don't do all that much anyway (except use up space within the pot), from what I have observed. Ideally you want to mix some rock evenly into the soil. I use pumice but whatever is cheap and available should work. An all-organic soil mix will stay wetter longer and makes it trickier to manage the watering cycle. If the pots are right on the windowsill next to the glass and they get hours of sun through the window every day, that should be okay for now. Whatever window you have that gets the most sun.
