@TurtleTots:
The following steps worked for me on my iPhone Kobo app. I assume that they will also apply to the Galaxy S4, which I think is the Android version.
- Go to the Home page in your Galaxy/Android Kobo app
- Tap the Flag icon in the Title Bar. This brings up a list entitled Kobo News
- Scroll to the last item in the list. It is entitled: Did you know? How to Sideload Books to your Kobo App.
The procedure is set out in a series of steps, for each of the different apps you can use to do this.
Good luck.