Honestly, anywhere is fine. If you put it ina hide, it will make a more humid microclimate which can be good. If you put it under the che it will dry out faster. A few clumps in the corners or wherever should help. It will take some larger handfuls in order to hold enough moisture to last awhile. Remember, the point of it is to hold enough water to provide a stay source of humidity for awhile. Having enough of it matters more than where you put it.