Trying to put a canvas in Google Cardboard

Hi there!

This is the case:

I want to make a some kind of scrolling menu to cardboard, who shows itself pressing a button and stuff, that's not important here.

The thing is that I can't see the canvas when I press play, and I don't know how to do it.

I apologize if my english is bad, it's not my mother language and I'm tryinig to learn ^^ thank's to everyone.

I'm using this cardboard SDK and Unity 5.6.2f1 bytheway, I thougth it could be important to say it.