Linux organizes all data into files stored inside directories (folders). Directories themselves are just special files that contain a list of names pointing to other files or directories. The entire structure forms a single inverted tree rooted at / (the root directory). There are no drive letters — every device, partition, and network mount gets "grafted" onto a branch of this one tree.
Every file has metadata beyond its name: an owner, a group, permissions, timestamps (access, modify, change), size, and an inode number. Commands like stat and file let you inspect this metadata. The find command lets you search the tree using metadata criteria — name patterns, file types, sizes, timestamps, and more.
The RHCSA expects you to fluently create, copy, move, rename, and remove files and directories from the command line, inspect their properties, and locate them anywhere in the filesystem.