An example path of an arc path named mod file would be UltimateModManager/mods/organized_css/ui/param/database/ui_chara_db.prc, and it would show up in the application as organized_css. All uncompressed mod files must be in their data.arc folder layout and have the correct original naming.
Compressed mod files may start with their offset in hexadecimal, such as 0x35AA26F08_model.numatb or be named by their path within the data.arc. Folders at the top-level here will be the selectable modpacks. Put mods in sdmc:/UltimateModManager/mods.Download the latest from the releases page.