Good link! Glad you found your answer. An album in Lightroom CC is like a collection in Lightroom Classic CC; that is to say, somewhat like a "play list" in iTunes or Spotify. Any one image can be in multiple albums, or you can remove it from all albums, in which case it is still in the catalog (in a folder, using Lightroom Classic CC terminology). Folders are representative of physical image locations, while collections/albums are just lists of images that "go together."