The six dismounts are broken into two 3-man fire teams, and will operate the same way the two four-man fire teams used to, obviously with just one less member. The commander will always be with the main effort, so if the main effort is dismounted then the commander will also dismount. In that case the vehicles will generally be commanded by the mech corporal or mech sergeant. The exact ways to go about this are very technical and depend on unit SOPs.
You need to remember what happened before the PMVs were invented. In the good old days (ie, a couple of years ago), the light infantry used to get driven around the place by trucks (generally Unimogs), either from the battalion's transport platoon or from the CSSB. Those trucks would have a single, generally very junior, driver in each, and that's it. If he was lucky the packet commander might have a map and radio, but he usually didn't. He simply got told to drive somewhere, pick up some grunts, then drive somewhere else. Compared to that, the idea of a few Bushmasters, each being armoured, having integral radios, and being driven by an infantryman, being in a zulu muster somewhere is not that big a deal.
To expand, the exact same thing happened in Afghanistan. The PMVs attached to the special operations task group were driven by whatever random diggers could be found spare in a brigade with a driver's ticket, normally under the command of an RAAC officer. They would be told to drive the operators somewhere, who would then jump out and go off to do their mission, and the drivers would sit somewhere in a zulu muster, without any security. When the mission was complete, the PMVs would drive unescorted to where ever they needed to go to pick up the operators, often through unsecured areas and often through harassing fire. It was pretty loose compared to what the conventional diggers over the fence were doing, but it worked well enough.
As an aside, if you are interested in a bit of reading, the Army has declassified a lot of doctrine and put it online - Doctrine: Army Doctrine | Australian Army.
It is all pretty high level, as none of the procedural doctrine has been uploaded, but may still satisfy some curiosity. If they ever upload the mounted minor tactics pam or the brigade concept of employment document, that would be of particular interest to you.
Thanks again
With time I'll do some more homework with what was suggested.
Can relate to moving troops from A to B with Unimog's, as spent some time in the transport Platoon.
As a reservist in the 80's our Zulu muster was more of a tactical BBQ.
I'm sure Pucka was much safer than Afghanistan.
Well done.
Regards s