adding shortcuts to my desktop

If you're talking about a file, in MacOS, they're called Aliases, not shortcuts. There are three methods to create one:

• Click on the file, and then type [cmd]-L (Command is the "Apple" key or the ones just outboard of the space bar)
• Right-click on the file, and from the pop-up menu that appears, choose "Make Alias"
• In the Finder, click on the file, then go to the Finder menu, choose "File," and "Make Alias" from the drop-down menu

Then, just drag your Alias wherever you want it.

If you're talking about a web site bookmark/Favorite, in Safari, just click and drag the "Favicon" that appears to the left of the URL over to your desktop.