Here is a good video that explains support and resistance in forex trading. Support and Resistance is a very basic yet highly essential concept that every trader must know. Forex Traders often target these areas of support and resistance to take profit, stop loss, as well as enter a trade.
Double and even triple tops/bottoms are very common in the daily markets. The more times currency price bounces off these support and resistance lines, the stronger they are. This also means that if a triple bottom support is broken, also known as a breakout, the price is likely to go even lower than when a double bottom support is broken. The same theory applies to resistance.
But do take note that there are often false breakouts, whereby the support/resistance is broken only for an instant, and immediately retraces back to the opposite direction.
