Your foot is on the end of your leg. You use your feet to stand on. You have five toes on each foot. You wear shoes and socks on your feet.
Put means to place something somewhere, or to stay in one place. For example "stay put" or "put it down".
Soot is a black powder that is left behind when something is burnt. The piece of wood in the picture hides an engine and you can clearly see the soot marks left by the exhaust.