[Ask] How to use HANS to play undub roms

Hardware : New 3ds XL
Sysnand : 9.8.0-25.U
Game Card : Sky3ds
Homebrew Channel : Ninjhax 2.5

Does anyone can tell me how to play undub roms step by step? I've already got the Rune Factory 4 (RF4) USA and RF4 undub rom. Since i kinda confuse for part like romfs, etc

thanks in advance