Every candle has an Open, High, Low and Close price. The rectangle body is the range between Open and Close; the thin lines above and below are the highs and lows reached during the period.
Green (or hollow) candle = Close > Open (price went up during the period). Red (or solid) candle = Close < Open.
A candle on the daily chart summarises one full trading day. On a 1-hour chart, one hour. On weekly, one week.
Reality check: candlestick 'patterns' work far less often than social media suggests. They're useful for describing what happened, not for reliably predicting what happens next.