The RSI is a price-following oscillator that ranges between 0 and 100. Generally, technical analysts use 30% oversold and 70% overbought lines to generate the buy and sell signals.
• Go long when the indicator moves from below to above the oversold line.
• Go short when the indicator moves from above to below the overbought line.

Note here that the direction of crossing is important; the indicator needs to first go past the overbought/oversold lines and then cross back through them.