The Dock is one of the primary elements of the macOS user interface. You can use it to launch apps. You can customize which apps appear in the Dock and in what order the appear. You can also play files and folders on the right side of the Dock. You've got several preferences you can set to change the Dock's appearance.
In macOS you have the option to have the Dock always be present, or to have it automatically hide itself until the cursor is at the bottom of the screen. Both options have their advantages and disadvantages.
The right side of the Dock can be used for easy access to files and folders. By putting aliases to folders on the right side, you can have access to the files in them without needing to open a Finder window. You can set these folders to appear in three different formats. It is important to understand that these are shortcuts to the files, and not the files themselves.
It is important to understand that the app icons shown in the Dock are not the apps themselves, but simply shortcuts to the apps. You can easily remove or add shortcuts, but this is not the same as removing or adding apps to your Mac. You can also access special functions of these apps through the Dock, and use these shortcuts as drop targets for documents.
Most Mac users use the Dock many times per day. So it would be worth the time to optimize your Dock. Add your most commonly used apps and remove others. Arrange your apps to make them easy to find. Add folders and files to the right side and set them to appear the way you want. Change your Dock settings to get the most from it.
Learn how to use and customize Stacks, a feature of the Mac OS X Dock. You can quickly access your files or applications through Stacks. They can be configured to show grid and list views. You can create custom stacks to hold specific items.