Bollinger Bands are used to measure the volatility of the market. Basically this means when he says the market is quiet and when it is moved. When the situation is calm, the bands are quite contracted, however, when the market begins to animate the two bands expand.
A useful thing to know about bars Bollinger is that the price tends to return in the middle of the bands. This idea is the basis of bounces that occur near the band, bringing the price back toward the middle. This is because Bollinger bands serve as support and resistance, the higher the timeframe used most of these will be strong.These bounces are often used by traders in situations where the market does not show well defined trends.
One aspect that must also be taken into account is the crushing of the bars towards each other (also known in English as Bollinger Squeeze). When the bars are close to each other, usually means that it is approaching a breaking point. If the candles start to exceed the upper band usually continue the movement upward, while a break down will be a sign of a negative price movement.







