It's basically the same system as England, it's based on it so yeah.
We elect a party to power, then that party appoints ministers from the elected people and normally the appointed Prime Minister is the leader of the winning party.
In this case, the last PM stepped down and in doing so, the House of Commons was "put on hold" while the party elected a new leader. The Governor of Canada then appointed that new leader as PM so he can assure the transition but he needed to trigger election before the House of Commons work resumed which was today.
So now we get a snap election of 36 days to appoint our new government but in the meantime, Marc Carney is the acting Prime Minister.