Depending on your setup, the DOS FAT or VFAT may already have been mounted. If not, then, first create a Directory under /mnt, e.g. a directory called dosdisk under /mnt:
[root@localhost /]# mkdir /mnt/dosdisk
Next, mount the disk as in:
[root@localhost /]# mount -t msdos /dev/hda2 /mnt/dosdisk
or
[root@localhost /]# mount -t vfat /dev/hda2 /mnt/dosdisk
Please note that you have to change /dev/hda2 mentioned
here to whatever device name you are mounting.