The advice you were given assumed you're using KDE. Unless you installed KDE yourself, VL 6 Standard uses XFce.
To add a desktop icon to launch Firefox, right-click on any existing desktop icon, then click on Desktop, then Create Launcher. Then fill in the blanks. When you get to the icons box, if you want the "foxy" Firefox icon, Select Icon From: Image files. Then click on Pixmaps and find the Firefox icon. Double-click on it and there it is! Finish by clicking on Create.