Lightroom can be a confusing experience for many new users. This article from Pixiq may help to clarify things. It begins,
Lightroom has the joy of being simple to start with, but still having hidden depths. Sometimes this means we see things that can confuse new users when looking for solutions to problems. Sometimes these are in the form of homonyms, other times in how Lightroom works internally.
Helderberg Photographic Society 