download the homebrew starter kid if you haven't already, put all the files from it in your sd card.
start homebrew channel and look for menuhax manager 2.1
install
you can now enter homebrew at any time by holding L when the home menu is loaded (like when you boot the 3ds up or when you start a programm and press the power off butten, then hit the home button to return to home menu)
now, entering homebrew channel through the hold L way, you can start old eshop downloader app and download ironfall
after you downloaded ironfall, start the game once and exit it again.
go back into homebrew channel and look for the ironhax installer and install ironhax.
you can now enter homebrew through the game ironfall even after an update. (but dont update ironfall, ignore the update message). you could change your homemenu design now, but you'd lose menuhax which is a nice backup entrypoint