To copy text, select it and use the → menu item. Additionally, selecting text with the mouse will cause selected text to be copied to the X selection.
To paste the text currently in the clipboard, use the → menu item.
Additionally, text selected with the mouse may be pasted by clicking themouse button at the desired position.
If you are using the KDE desktop, you can retrieve earlier copied text from any application using the Klipper icon in the system tray.