to trade gaps, there are several ways. some use indicators either trending indicators or oscillators. it is also possible to use price action. simple price action would at previous support or resistance levels for a turn around point. other times, you may be trend spotting, fractal counting, or looking for some kind of price action pattern. generally speaking, i don't like to trade gaps. some sell on gap ups and buy on gap downs. it works some times, but not always.