Massive stars (M > 8 Msun) in the Milky Way are overwhelmingly (>80%) found in binaries or higher-order multiplicity systems, which play a curial role in governing cluster dynamics and stellar evolution.  Massive stars and their clusters are known to form from molecular clouds. However, our understanding of their formation processes, from ~10 pc scale molecular clouds to 100 AU scale multiple systems, is still limited. To investigate the formation of massive stars and their associated clusters across multiple scales, we conducted a systematic program using  interferometer observations. Our studies have provided promising insights into the formation of massive protostars and protoclusters at various evolutionary stages and physical scales. In this talk, I will present a detailed overview of our recent studies on massive star-forming regions using ALMA observations, ranging from ~10 pc scale down to scales of ~100 AU.