I don't quite understand how voting in Canada works.
Do you vote for the person or the party?
How do they decide who is the party leader?
Does the leader have to have a senate seat?
This is all very confusing to me.
You can vote for the person or the party, but to do the latter you have to do the former for the person representing the latter... No wonder you're confused. Party leaders are chosen by party members at a convention designated for the purpose, and no, the leader does not have to have a senate seat. In fact most voters would view that as a liability, though I don't think there's any rule against it. To begin at the beginning....
There are two levels of government involved here, just as in the United States' system you might be more familiar with, the federal and the provincial, and they're quite separate, just as the U.S. federal and state governments are separate. I presume it's either the current Ontario provincial election that's confusing you, or all the loose talk about a federal election when we had one two years ago?
Every province is divided up into geographic areas loosely based on population numbers, variously and confusingly called constituencies, ridings, or seats, which are roughly equivalent to the Congressional Districts you might be more familiar with. There are both federal and provincial constituencies, and in general they are different sizes and have different boundaries, there's no connection between them, though no federal constituency crosses a provincial boundary. Party members in each constituency meet and nominate a candidate to stand for election on behalf of the party in that constituency. Individuals can also run as independent candidates, but that doesn't happen much and the chances of success are very poor without an organized political party backing them.
Voters within each constituency on voting day get a ballot that lists everybody who's trying to get elected there, showing their party affiliation or independent status, and they have to pick one. When the dust settles after voting day, the party that elected the most members gets to be the government, and the leader of the party gets to be the Premier in the case of a provincial election, or the Prime Minister in a federal election. It's what we call a first past the post system, which really means you don't need 50% plus 1 of the votes in a constituency to win it, you just need to get more votes than anyone else does. If there are four parties running candidates in a particular constituency, for example, you can win it with 25% of the votes plus one more. In most constituencies there will be at least three parties active, so in practice you don't need the support of much more than a third of the voters to form a government. Not very democratic, I agree, and it leads to levels of party representation in our elected bodies only distantly related to the way people voted.
No doubt you've also heard talk of minority and majority governments and wondered wothehell that means. That's an institution peculiar to British parliamentary systems called responsible government, and in practice it means a government can continue in office only as long as it retains the support of a majority of the elected members. The government is responsible to the House of Commons at the federal level, and to the provincial legislature at the provincial level. Not a problem if the party won a majority of the constituencies in the election, which is usually what happens, but our current federal government didn't, it holds less than half the seats in the House so its situation is a little precarious. If it's defeated on a vote in the House in a particular way, on what's called a confidence motion, it cannot continue as the government, it has officially lost the confidence of the House and there'll have to be an election, except under very unusual circumstances which have occurred only once in the 140-year history of this country.
That came to be known as the King-Byng affair, after the names of the principal characters involved, the Prime Minister at the time, Mackenzie King, and the Governor-General, Lord Byng. It was one of the rare circumstances under which the monarch, in the person of the Governor-General representing the Crown, has some real power. If a government falls on a confidence vote and there is another party in the House with enough members and the support of some others that it might be able to form a government, the Governor-General can ask the leader of that party to try, which is what happened in the King-Byng affair. We're close to such a situation in our federal government now. The Liberals and the New Democratic Party together have almost enough members to form a majority, they're natural allies in many ways, and given the ideological divides among the other parties in the House, it's the only possible workable alliance. Because the Liberals and the NDP don't have a majority of the seats in the House, there would certainly be a federal election if the Conservative government falls, but if either of them had won just a few more seats in the last election we'd have a very interesting constitutional situation here.
All of this applies at both the federal and provincial level. Each province has a Lieutenant-Governor with powers and responsibilities similar to the Governor-General at the national level.
Does that clear anything up, or have I just made it worse?