You can add a launcher to a panel in one of the following ways:
From the panel popup menu
To create a new launcher, right-click on any vacant space on the panel, then choose Add to Panel -> Launcher. A Create Launcher dialog is displayed. For more information on how to complete this dialog, see To Create a Launcher With the Create Launcher Dialog.
Alternatively, to add an existing launcher to the panel, choose Add to Panel -> Launcher from menu from the panel popup menu. Choose the launcher that you want to add from the menu.
From any menu
To add a launcher to a panel from any menu, perform one of the following steps:
Open the menu that contains the launcher from the panel where you want the launcher to reside. Right-click on the title of the launcher. Choose Add this launcher to panel.
Open a menu that contains the launcher. Drag the launcher on to the panel.
From the file manager
To add a launcher to a panel from the file manager, find the .desktop file for the launcher in your file system. To add the launcher drag the .desktop file to the panel.