If anyone wants a simple file navigator to launch dos games in DOSBox, follow the instructions below:
Step 1) Start DOSBox for the first time, then type exit (Left shoulder button opens a virtual keyboard) to quit the emulator.
Step 2) Mount the SD to your computer. If you haven't already, make a roms folder called "DOS"
Step 3) Go to the following website and download Dos Navigator 1.51 Freeware Release from the Dos Navigator 1.51 binaries (786K) link on this page:
https://www.ritlabs.com/en/products/dn/
Step 4) Unzip dn151.zip into your DOS folder in roms
Step 5) Using notepad on your computer, edit the dosbox-SVN.conf file from .dosbox folder and type after the #comments in the [autoexec] section on their own lines, the following and then save the file:
mount c /mnt/int_sd/roms/DOS
c:
dn.com
Step 6) Copy your dos games folders in the DOS folder in roms. Dos Navigator automatically shows what's in the directory that its executable files are located so I find it easiest to copy my game folders into the same directory.
Step 7) Reboot the RS-97 and open DOSBox. Dos Navigator will automatically load. Use D-Pad to move around files/folders and start button to open a folder or execute a file. After you exit a game, Dos Navigator will automatically reload.