Hi,
The firemen had arrived or arrived to fight the fire, which was spreading quickly.
They used their hoses to spray water on it. One of them heard a child crying, so to save it he used a ladder to enter the flat through the open window. The crowd cheered when they saw him carrying the child down.
Soon the fire was put out and the firemen left.
I've just editted it for good English, not for what is suitable for the level of the students. Perhaps you can decide better about that?
Best wishes, Clive