@tjf No VMs (virtual machines) are involved, you just start each vault in a separate terminal/console window. Full instructions for this are, as I think you found, in the 31st August Dev Update..
If you aren’t technical, building from code is probably best left for now, as at the end of this sprint (2-3 weeks) there will be a new set of installers and we will be able to link all our vaults into one big network!