Hi there.

You suppose to have 2 option to play music on this device:

1. Music application

- From any Home screen, tap the Apps icon. Tap Music.

- Drop down and select from the following:

Playlists

Tracks

Albums

Artists

Folders

Devices

- Navigate to the desired file and tap it to play.

2. Play Music application

- From any Home screen, tap the Apps icon.

- Tap the Google folder.

- Tap Play Music.

- Tap Menu icon (top left) and choose from the following:

Listen Now

My Library

Playlists

Instant Mixes

Shop

Download only [On/Off]

Settings

Help

Send Feedback

- Follow additional prompts, tabs, and settings in each section above to locate and play music

I had a Galaxy Core Prime before and the default music player was Google Play Music. It could be the same with the Galaxy Grand Prime.