How to notate resonance mechanisms

The way we portray these mechanisms is slightly different from our reaction mechanisms.

The main difference here is the use of square brackets around the mechanism as well as the double-headed resonance arrow.

An example of this is shown in the resonance structures of phenol.

Figure 1: Phenol resonance mechanism

As you can see, the curly arrows are still drawn the same way as we are still depicting the movement of two electrons with each step.