In case you aren't aware of it, the Mint website Community page has links to Mint documentation. For example, from the Users guide:
Make your own shortcuts
If you don’t like the idea of having “Favorite” applications, you can simply use your
panel or your desktop to achieve similar results, (namely, giving yourself quick access to
your applications). Simply drag & drop the application of your choice from the menu to
your panel or to your desktop.
Try dragging a file to the taskbar to see if you can achieve the same result.
To remove an item from the taskbar, try right click on the taskbar to see the pop-up menu. There should be an option to remove items.