I run the Xfce desktop, so I can't confirm it, but I found this on the web about the Cinnamon desktop.
Applets are icons or texts that appear on the panel. Five applets are shipped by default, and developers are free to create their own. A tutorial for creating simple applets is available.
To install an applet: Download it and decompress it in ~/.local/share/cinnamon/applets.
Some useful stock applets include one for Accessibility, Brightness (helpful for laptop users), and windows quick list (great if you use workspaces).
If you click on Get new applets, you are taken to the Cinnamon website where there are a large number of applets including one for weather, screenshots, virtual box launcher and much more.