Who inherits, in general terms
Ontario's intestacy formula splits the estate between a spouse and children in proportions set by statute; if there's no spouse, it moves to children, then parents, then siblings, in a defined order. The exact split depends on the family situation and is worth confirming with an estates lawyer rather than assuming.
The step nobody expects: someone has to apply for authority
Unlike a will, which names an executor directly, an intestate estate has no one automatically in charge. A family member applies to the court for a Certificate of Appointment of Estate Trustee Without a Will, and until that's granted, nobody can legally list, sign for, or close on the house.
What this means for a timeline on the house itself
The house isn't going anywhere while this gets sorted, and there's no rush to decide anything about selling it during this stage. The one exception is insurance — an empty house still needs to stay covered and heated while the legal side plays out.