Go, but you can either place a piece or do a "copy" move that creates a new piece
You can place anything copied as long as it contains at least one of your color pieces

Hold C, hold click and drag mouse, then release mouse: Copy
With mouse, drag pieces around
W: Place white
B: Place black
D: Delete
U: Undo
R: Redo

This only works on desktop, and you need to remove surrounded groups manually