Candles are a simple method of representing price movements within a time segment. They show four price points - maximum and minimum ( wicks) and opening and closing prices ( the candle) The colour shows the direction of movement - red = bear, green = bull. You need to use some other indications to trade using candles, and two important ones are exponential moving averages, and volume. I use them for scalping Bitcoin, but it is a bit of an art form. There are loads of videos on YouTube about it, and here is just one ( not necessarily the best).
https://www.youtube.com/watch?v=ofltPl-52y8Take care when trading Bitcoin, as it is extremely volatile, and you should expect losses as well as gains. Start small, and don't use money you can't afford to lose. Scalping is used to make frequent small gains, so don't become greedy, and learn to take profits and losses.