When there is a fire in your home fire fighters will need to do the following to insure the fire is out:
Any windows that were broken, and any holes cut in the roof were for ventilation. Proper ventilation techniques used by fire fighters reduce horizontal fire spread in a building, and greatly reduce smoke and heat damage.
Openings in walls and ceilings are to insure that the fire is completely out. Any hidden embers could reignite later.
It is sometimes necessary to disconnect utilities to prevent further damage, and to insure the safety of fire fighters.
If tarps have been thrown over your possessions, it was to protect them from water and debris. The tarps need to be picked up by the Fire Department as soon as possible to be ready for use again.
An investigation of fires that harm people or damage property will typically follow the fire extinguishment. The Fire Investigator must make a preliminary determination of the origin and cause before the fire area can be disturbed.