Nova launcher home button issue

[AC Question]

I recently got a galaxy s6, I am trying to apply a theme to it. I downloaded a free theme, and nova launcher as I have used it in the past. When I applied the theme it appeared to work, however when I hit the home button on my phone it takes me back to the default home screen. I would like it to take me back to the themed homescreen. I don't want to have to launch the theme in Nova launcher every time I want my phone to look like this, I want to turn my phone on and have it applied already. It's been so long I can't remember how to do this. Any help is appreciated. Thank you.