This manual gives you a walk-through on how to use the Resonance Plugin:
The Resonance Plugin generates all resonance structures of a molecule. The major contributors of the resonance structures can be calculated separately.
As an example see the two structures below: the major resonance contributors of diazomethane, while the structure below them is its canonical form.
Fig. 1 Calculated resonance structures of diazomethane
Fig. 2 Canonical resonance structure of diazomethane
The following options can be adjusted in the Resonance Options panel:
Fig. 3 Resonance Options window