Music Speed Changer has a built in folder browser. It let's you browse through all your folders on your device and SD card. From it, you can
- Play the folder
- Play next
- Add the folder to the playing queue
- Add the folder to a playing list
- Set the folder as home directory
To browse folders, open the app main menu
Select Folders
From here you can navigate to the folder you wish
You can also browse your SD card (if available)
By clicking the three dots to the right of the folder, you open the folder menu. Your options are Play the folder, Play next, Add the folder to the playing queue, Add the folder to a playing list, Set the folder as home directory