Charcoal is a soft black substance that is left after something is burnt. You can use charcoal to draw with, like in the picture. Charcoal is messy, and you have to be careful not to get black fingerprints on everything when you are working with it.
Charcoal is also used as the name for a color that is very dark grey, almost black.
Coal is a type of black rock, made almost entirely of carbon. It is formed from old plant matter being squashed by the gradual movement of the earth over a very long time. Coal can be burnt, and is often used as the fuel for power plants. Coal is dug out of the ground, from coal mines.
Coal is not the same as charcoal, which is just the black residue after wood is burnt.
You control something or someone when you make it do exactly what you want it to.
The man in the picture is controlling a toy helicopter.
You enroll in something when you are added to a list, or roll.
Enrolling is usually used to mean signing up for some kind of course of education at a school or university.
