In order to create the legal entity, you need to incorporate as a non-profit. This is not a lot different than creating a for profit, but there are a couple of differences.
First, you need to decide if it is a federal corporation or a provincial one. Usually, this depends if you operate only in one province (which could suggest a provincial corporation), or if you operate (having offices, locations) in more than one province, which would make it federal.
Then you need to find at least 3 directors and write the letters of incorporations. You also need to create the bylaws in particular if different from legislation. A good place to start is to look at the Corporation Act for non-profits in Ontario which is pretty good for looking at the requirements.
If you want to have an official Name, you need to do a NUAS name search, however, it is also possible to run your non-profit only under a registration number.
Industry Canada has a good site for federal non-profits.
You can find similar for each of the provinces and territories.