The final step in mounting your filesystem is the actual mount point registration where the filesystem will manifest itself. The preceding two steps (the unnamed and the special device registration) are optional—you can write a perfectly functioning filesystem that doesn't perform those two steps, but performs only this mount point registration (e.g. the RAM-disk filesystem).
Apart from the initial setup of the filesystem, the unnamed and special device registration mount points are almost never used.
Once you've called resmgr_attach() to create your filesystem's mount point, you can handle requests for the filesystem. The resmgr_attach() function is called with a valid path given to path (for example, /ramdisk), a flag of _FTYPE_ANY given to file_type, and a flag of _RESMGR_FLAG_DIR given to flags (because you will support directories within your mount point).