What is RSI and how do you read it?

Above 70 is often called overbought. Below 30 is often called oversold. The usual setting looks at the last 14 candles.

The big beginner mistake: overbought is not a sell button. In a strong uptrend, RSI can stay above 70 for a long time while price keeps rising.

RSI is more useful as a clue about momentum, especially when it disagrees with price. That disagreement is called divergence.