SentinelHub EO Browser is, as the name suggests, a browser based explorer of Sentinel imagery
You can even download subsets of the data for free (requires login though). It's one of the simplest ways to get started exploring Sentinel imagery IMHO
Iain Woodhouse is a Professor of Applied Earth Observation at the University of Edinburgh, the author of multiple books & course on Synthetic Aperture Radar (SAR) and one of the best people to explain radar remote sensing with decades of experience teaching but also working in the industry.
You can even download subsets of the data for free (requires login though). It's one of the simplest ways to get started exploring Sentinel imagery IMHO
https://apps.sentinel-hub.com/eo-browser/