It's a form of obedience where you go around a course with signs that tell you what to do. To go from one sign to the next at your own pace, without the judge saying anything but "Are you ready? Forward!" in the beginning, and "Exercise finished" at the end.
Go to the Rally section of the forum, and you'll find a number of Kodi's rally runs for examples. It's fun, and although it's challenging to do it really well, the entry point is not as high as for formal obedience. (which Gemma and Kodi also do!
As far as training for it is concerned, in some places they have "Rally classes". My training center doesn't. But you can learn everything you need in a formal obedience class. Then print the signs out for your venue. American and Canadian rally is close, but not exactly the same, and then there is World Cynosport Rally, which is a little different from both of the national clubs. There are a couple of other venues as well, but I'm not sure if you'd find them in Canada. Once you have the signs and a copy of the rules, you can have your obedience instructor help you with any specific moves you don't understand. Novice level is pretty straight forward. (and on leash) the levels, of course, get progressively more difficult, and sometimes the sings (and the instructions that go with them) are easier demonstrated than explained in words)
I think you and Archer would be great!