Here is what I sue to make the chicken with the vegetables and potatoes.
In the pan I put potatoes, onions, carrots, celery, chicken liver and neck. I place the chicken on top of the vegetables and potatoes and then season everything with salt, pepper, garlic and Provence herbs mix the vegetables well and rub the chicken. Then I put just a little olive oil, mix well again so all the vegetables/potatoes are coated and rub the chicken as well.
I usually place the pan on a grill and not directly on the oven's floor, otherwise it tends to burn. Half time through I rotate the pan 180 degrees since my fire is only on one side.
The chicken dripping on to the potatoes provide the right amount of liquid so it doesn't burn ( most of the time ) and an amazing flavor.
Took me a few tries to get the temp and amount of embers just right so potatoes and chicken all cook properly. Oh the joy of WFO cooking :-)