Thanks guys for trying and your comments.
Every feature in Click Cutter setting panel has mouse over hints explaining how the feature works.
For those who is lazy enough to read the hints:
Auto-copy: highlight a text and hold a button until "C" appears. release a button. Done.
If you hihglighted and "c" appeared BUT you changed you mind and decided to CANCEL Copy then just move a mouse bit and "C' disappears. Nothing is copied then.
AUto-Paste: Click on the spot where you want to paste and hold the button until you see "P". Release the button and it's done.
ATTENTION: IF you hold a button for more than 2 seconds "p" disappears and that means Paste is cancelled. Another way to CANCEL paste is to move a button a bit.
Very easy!

If you want to replace a highlighted word please refer to a help file or read a hint in Setting panel.
NOTE: currently PAste works only on WHITE background only. Too long to explain why.