here you go. The body is the volume for that period, a period could be a second, a day or a month, depending of the chart you are looking. In day trading you look at the second.
Each candlestick has the entire history of the stock for that period. Opening price, closing price, volume.
The more volume there is, the shorter the top or bottom stick are. A candlestick with no stick is called a marubozu which could be either good or bad, the white being the good guy.
So every second a candlestick is formed. A group of candlesticks indicates a pattern, bearish or bullish. And this is what the Japanese understood since the 17th century from trading rice.