Application Finder (xfce4-appfinder) is a launcher for programs, where you can type in a program name. Default keyboard shortcut is Alt+F3.
You can also run this in collapsed mode to be more like MacOS’s Spotlight - xfce4-appfinder --collapsed - default keyboard shortcut is Alt+F2.
Panel (xfce4-panel) is a tool that can create panels at the top and bottom (like MacOS/Windows) of the screen. You can add/remove panels and Items on each panel.
Troubleshooting
The taskbar is missing
Drop to a terminal (Ctrl+Alt+T) and run xfce4-panel &