The Dock does two of the taskbar's four jobs. It shows pinned apps and running ones (a dot under the icon means running, once you turn the dots on), and clicking an icon brings its windows forward. It does not show a preview of each window, and it has no Start button or tray.
- Pin an app: open it, right-click its Dock icon, Options → Keep in Dock. Drag icons to reorder, drag one out of the Dock to unpin.
- All programs: drag the Applications folder from a Finder sidebar to the right side of the Dock, next to the Trash. Click it for a grid of every app.
- Downloads: the folder on the right side of the Dock fans out recent downloads.
- Minimized windows go to the right side of the Dock as separate tiles. System Settings → Desktop & Dock → "Minimize windows into application icon" puts them into the app's icon instead, like the taskbar.
- Window previews do not exist. Right-click a Dock icon to see the list of its windows by name.
The Dock can auto-hide (Desktop & Dock → "Automatically hide and show the Dock") and sit on the left or right edge. Its icons stay a fixed size unless Magnification is on.