Like most windows tools Schemata uses Control-X to cut, Control-C to copy and Control-V to paste.
The cut operation removes any selected objects and cuts any wires at the boundary of the selected region (if there is one). Thereafter paste will put the cut objects at the mouse and allow you to re-position them prior to pasting. Note that moving the mouse to the edge of the visible schematic area will initiate a scroll to allow you to place objects at a place that is perhaps out of view while cutting.
The copy operation works similarly to cut without removing the objects from the drawing. Copy also places a bit-map of any selected objects onto the windows clip-board for use as a picture (in Paint or Word for example, paste will insert the schematic as a bitmap image). If no objects are selected copy will place the visible schematic on the windows clipboard. Please note that if the “Write LISP form” option is selected in Preferences then when copy is used with no objects selected a text form will be placed on the windows clipboard (in addition to the picture) so that second Schemata window (perhaps on a Remote Desktop connected PC) can paste the entire schematic object. More about the Write LISP form option.