To compactify 2 open dimensions to a torus, the method of identification written down for this example as
$$ (x,y) \sim (x+2\pi R,y) $$
$$ (x,y) \sim (x, y+2\pi R) $$
can be applied.
What are the methods to compactify 6 open dimensions to a Calaby-Yau manifold and how exactly do these methods work?