This article provides a practical guide to single-molecule Förster Resonance Energy Transfer (smFRET) techniques, focusing on the study of immobilized molecules to measure reaction trajectories from milliseconds to minutes. The authors highlight the importance of smFRET in advancing biological research, particularly in understanding protein folding, conformational dynamics, and interactions. They discuss the key components and experimental design, including the selection of suitable fluorophores, enhancement of photostability, and surface immobilization techniques. The article also covers the technical aspects of data acquisition, such as total internal reflection microscopy and emission detection, and provides guidelines for data processing and analysis. Additionally, it addresses limitations and advanced techniques, such as three-color smFRET and the integration of force measurement with smFRET. The authors aim to facilitate the use of smFRET by researchers, emphasizing its potential to revolutionize the study of biomolecular interactions.This article provides a practical guide to single-molecule Förster Resonance Energy Transfer (smFRET) techniques, focusing on the study of immobilized molecules to measure reaction trajectories from milliseconds to minutes. The authors highlight the importance of smFRET in advancing biological research, particularly in understanding protein folding, conformational dynamics, and interactions. They discuss the key components and experimental design, including the selection of suitable fluorophores, enhancement of photostability, and surface immobilization techniques. The article also covers the technical aspects of data acquisition, such as total internal reflection microscopy and emission detection, and provides guidelines for data processing and analysis. Additionally, it addresses limitations and advanced techniques, such as three-color smFRET and the integration of force measurement with smFRET. The authors aim to facilitate the use of smFRET by researchers, emphasizing its potential to revolutionize the study of biomolecular interactions.