Divergences not only signal a potential trend reversal; they can also be used as a possible sign for a trend continuation. Always remember, the trend is your friend, so whenever you can get a signal that the trend will continue, then good for you!
Hidden bullish divergence happens when price is making a higher low (HL), but the oscillator is showing a lower low (LL).
This can be seen when the pair is in an uptrend. Once price makes a higher low, look and see if the oscillator does the same. If it doesn't and makes a lower low, then we've got some hidden divergence in our hands.