Getting water out of the property as quickly as possible is the priority, standing water left in place accelerates mould growth and material damage, particularly to carpet, underlay and any timber flooring or skirting in contact with it.
Ventilation matters just as much, opening windows and using fans or dehumidifiers where available helps start the drying process immediately, even before professional equipment arrives, every hour without airflow increases the risk of mould taking hold in damp materials.
Documenting the damage with photos before cleanup begins is worth doing for insurance purposes, and calling in professional flood cleaning as early as possible in that first day makes a genuine difference to the outcome, both in terms of what can be salvaged and in limiting mould risk down the track.
