This bootloader uses the same configuration as bootctr. 
If you use delebiles arm9loaderhax you can put the arm9loaderhax.bin and the arm9bootloader.bin file on the root of your the 
sd-card, if you use my forks arm9loaderhax you only need to use the arm9bootloader.bin.
This bootloader defines which payload should be bootet by the key you press while powering on your 3DS.
Use the example config and the github release page to find out how to use the new features.
