The modifier keys on your Mac keyboard are the Command, Option, Control, Shift and fn keys. You use them for keyboard shortcuts and other functions. Since they differ from Windows modifier keys, it can take new Mac users time to learn how to use them.
There are many ways to rename a file or folder on your Mac. You can do it in the Finder with a menu bar command, a keyboard shortcut or the context menu. You can also rename files while working on them in apps. There are also options to batch rename multiple files.
There are many different ways you can launch apps on your Mac. You can use the Dock, LaunchPad, Spotlight. But it is also important to understand where the apps are actually located. There are also other ways like double-clicking a document or switching to an already-running app.
Split View allows you to place two application windows side-by-side on your Mac with no other windows or elements. You can use this as an alternative to arranging windows on your desktop or using a single window in Full Screen mode.