Upvote:3
The official instructions can be confusing, since they attempt to cover every possible situation, and much of what's written doesn't apply to you (or to anybody!). It would be less confusing if they wrote separate instructions for each different type of visa someone might apply for, but they didn't do that. They just threw everything together.
This is what you really need to do:
After you've submitted your application online, you need to print the page showing a barcode. You will include this page in the document package you send to the Visa Application Centre serving the area in which you live.
Your document package includes a copy of the Document Checklist, a printout of the page containing the barcode shown to you when you completed your application online, the necessary documents listed on the Document Checklist (not all of these will apply to you, but you should include anything you have which is listed, such as a copy of your I-94 and I-20), two passport photos, and of course your passport.
Mail or hand deliver the document package to the VAC using their official instructions. You should not need to pay anything, as transit visas are free and you will not need to give biometrics.