Can I hook up my Roku to my phone

For what purpose? There is a Roku app in the Google play store, but it doesn't allow you to watch content from your Roku on your phone screen. It acts as a remote control, assuming the phone and the Roku are both on the same private (not hotel or dorm) network. The app does allow watching The Roku Channel, but it doesn't require a connection to the phone for that. And if you're somewhere with a computer you would likely prefer watching it on a larger screen anyway.

And rolling back to my first statement, you cannot watch something playing through the Roku device on your phone. It's not designed that way.