Direct light would be like the sunshine, a camera's flash, photographic lights, or a bare light bulb. Indirect would be any direct lighting that is bounced off a surface, or shines through a surface, to be diffused. Daylight on an overcast day, a light bulb diffused through a shade, flash bounced off a surface, photo lights shining through or bounced off umbrellas, light in a light tent, etc. For a combination, use both. You could have a light shining on someone, and some of that light bounced back from another direction, for instance.