gnome-session-properties

cinnamon vs gnome : Cinnamon inherits many of its features from Gnome itself. Thus in most cases, you can use the gnome functionality to achieve capabilities that are not explicitly wrapped up in the main Cinnamon desktop.

In this case you can use gnome-session-properties

You can also just write "start" in the menu / search box and you will find the icon to setup the startup application

A cinnamon applet

There are many applets available that wrap just this functionality for you.

Extracting this applet to ~/.local/share/cinnamon/applets gives you a session applet in your tray:

Startup folder

Open ~/.config/autostart folder and you will find some .destop files wich are shortcut of startup program