In a nutshell, it’s like English’s they (plural animate or inanimate), it (for feminine objects, remember that german is a gendered language like french) she, and you (both singular and plural) combined.
Though, Sie meaning “you” is the polite version, used to address someone politely. For informal situations, there’s the impolite and always-singular “Du”
While there are different conjugations and capitalization between the different uses of Sie, in the end they all use the same word.