The easiest way to move files in the KFM is to open two copies of the KFM and drag and drop files between the two.

To start another copy of the KFM you can click the home folder icon on the Panel or select a directory from the Disk Manager section of the Application Launcher.

Once the second copy of the KFM is open you can simply click and hold the right mouse button on the file you wat to move and, while still holding the mouse button, drag the file to the second copy of the KFM. Once the file is over the directory where you ant to place the file, let go of the button and the file will be moved.