Broadly speaking, investors want to buy when markets are low so they can sell higher at some point in the future, and thus make a profit. Conducting technical analysis before entering a position is one way to try to identify price levels that might be considered low.
There’s no single, all-encompassing method for crypto technical analysis. Each trader will prefer to use different indicators and will likely interpret them slightly differently. It should also be noted that no technical analysis is anywhere near 100% predictive.