All moving copying and deleting is done by dragging.
Point to your first clip, hold down the left mouse button and drag it to any slot in the palette area.
You have moved your clip to the palette.
Now point to it again and drag it to the right hand column - This time, hold down the RIGHT mouse button.
This time you have copied the clip.
With the sole exception that clips cannot me moved to the clipboard, you can copy or move clips in any direction between columns - Use the LEFT mouse button to MOVE and the RIGHT mouse button to COPY.