The prime minister the leader of the party that can secure confidence of the house. That 33% represents the number of people who voted for liberal members of parliament. Currently the liberals have the most seats but not greater than 50% required to make a majority.

The conservative party is the official opposition with the second most number of seats.

Because the liberals and Justin Trudeau have a minority government they have to maintain support from other parties and often have to capitulate to their demands for that support.

All the legislation put forward by the Liberals is DOA unless they can get another party to support their bills. You require a majority of the voted from members of parliament to pass a bill on to the senate.

The conservatives tried a none confidence motion several times in one week but not even the Block Quebecois wanted to support their motion so it was DOA.

So unless Trudeau pisses off the other parties enough or Pierre Poilievre learns to actually play nice with others Trudeau shall sit as the Prime Minister until the next election.

So when you look at the power structure being Libs + NDP in a coalition accounts for greater than 60% of the votes cast that coalition actually reflects what Canadians actually voted for.