To see the full list of panels available and turn them on/off, simply right mouse click over the Ribbon or any Toolbar, then from the options menu that opens, browse the Panels list. To turn a panel on/off, pick it on the list. Panels with ticks beside them are ones that are already open.
Once a panel has been opened it can be arranged anywhere on your screen, and if you have multiple screens, then you can drag them to one of these to keep them handy, but not in the way of your drawing window.
As an example I've opened the Content Browser panel. This panel allows you to list folders to browse for drawings. From the panel you can preview and open drawing files. You can also preview the blocks held by a drawing, and if you want to use any of them, you can simply drag and drop them onto your drawing window to insert.
Panels can be arranged individually, or grouped together by docking them. To dock a panel, drag it by its title bar and drop it on an existing panel to group.
With panels you also have the option of displaying them in a stack, where they display as a compact toolbar, with the panels flying out when you pick on their icon. Alternatively you can have it tabbed, where the panel remains open with tabs at the top to switch between.
To switch between Icon or Tabbed panels return to the right click options menu, and from Panel stacking select:
