The J=O corresponds to L and S parallel and pointing in opposite direction such that the two components cancel each other and the total angular momentum becomes zero.
The J=1 corresponds to L and S being perpendicular to each other such that only one of them contributes. The other component is then zero in the direction of the total angular momentum;
The J= 2 corresponds to L and S parallel and pointing in the same direction such that they add up to each other.