Writing your thesis or dissertation proposal - or prospectus, as some departments at UBC call it - is the first step in getting writing. It can often serve as the backbone of your thesis, helping you to structure your introduction, literature review, methods section, and more. The resources listed here can help you to begin your writing journey.
Note that the Faculty of Graduate and Postdoctoral Studies does not have particular requirements for how proposals or prospectuses should be written, although there are general guidelines given in the Handbook of Graduate Supervision. Check with your department to see what their specific requirements are.