Van der Waals forces include attractions and repulsions between atoms,
molecules, and surfaces, as well as other intermolecular forces. Its different from covalent or hydrogen bonds because these two are much stronger. The Van der Waals interactions are caused by changes on the polarization of the molecule. They are ionic bonds.
If one part of a molecule is charged with (-) and the other is charged with (+), they are likely to attract by Van der Waals bond. These are also called "dipole-dipole" attractions.
Covalent bons are much stronger because they involve the sharing of electron pairs.