Ontario Taxes

I’m on disability (ODSP), before I was on disability I never made enough money to HAVE to file for taxes and with the fuss everyone made about what a pain in the butt they are I never bothered to do it. Seeing is how I’m trying to move this year,I figure now would be a good time for a refund, and someone told me that I can claim my rent on my taxes but I have to get the form to do it.

Where does one find this form? I’ve been all over the CRA website and I find info on rental income, which I’m pretty sure is not what I’m looking for.