The citizen parliamentarians would typically sit at tables of around 10 people, together with a facilitator and a note-taker. They would discuss proposals and issues and the facilitator would ensure that everyone's voice was heard and no one dominated the discussion.
All the tables would be networked together and a "theme team" could see what issues and options every table was discussing and would identify the top themes. These themes (or issues or options) would be presented to the entire parliament and all the participants would have voting keypads to confirm (or not) that the options had been identified and ordered correctly.
The parliament could call experts or witnesses to present information to the entire assembly, or present detailed reports. Questions could, of course, be asked.
The tables discuss and refine all the top options, finally voting for their preferred outcome. In this way decisions are made.
This is obviously a brief and very simplified description to give the general idea. The exact process would be far more detailed and precise.