Unlike fundamental analysis, which is based on macroeconomic and microeconomic rules and patterns, technical analysis mainly uses quantitative analysis. It comprises rather complex formulas for forecasting the future prices through the study of past market data, primarily price and volume.
To become familiar with this rather difficult approach, first see our video.
There is also vast amount of literature on the topic, for further reading we recommend, among many others:
Technical Analysis: The Complete Resource for Financial Market Technicians by Kirkpatrick, Charles D.; Dahlquist, Julie R.