Hello,
You can fill up your tax for 2019 online through software such as TurboTax. Go to Turbotax.ca and choose the online free version.
Since in 2019, you were here for only 1 day, the return will be mostly blank. You can skip through most of the sections.
Fill up your personal information and date of landing properly.
At the end you can print your return and mail it to CRA. As far as I know, you cannot submit your return online (which is called NETFILE) if you are a first time filer.
Regards,
BP