Barbecue

Do I take the lid off, keep the lid on and open the top vent, or close the vent?

Living on the continent we are not used to indirect grilling. Now I’ve bought a big charcoal barbecue with integrated thermometer, capable of indirect grilling. My first “project”:-) is grilling a whole chicken. I’ve marinated it according to recipes. Most recipes talk about “medium” heat. I guess for a gaz-barbecue this is easy, but how hot is this in a charcoal barbecue?