I would start with once a day to see how it goes. Let's say your going to take it in the am, so that I can give you an example:
So that would make it 2 hours after breakfast, supplements, meds, herbs. Be sure it is also 2 hours before you eat lunch or take any meds, supplements, herbs or more food. Otherwise the charcoal will absorb it all and take it out of your body before the body can use it.
And be sure to drink plenty of water during the 4 hours that the charcoal is working so that the things that the charcoal absorbs can be flushed out of your organs and out of your body.
Was I able to make it clear as mud for you?