Need an Introduction to Tiny Core? Or peruse Core Concepts.
Open a terminal window and type "emelfm /mnt" <cr> - for me this opens emelfm with the contents of /mnt in the left hand pane.
..and typing “ls /mnt” <cr> in the terminal window does what?
ls /mntmmcblk0p1/ mmcblk0p2/ sdf1/ sdf2/ test