Make a folder (name the folder that you want like deltarune pack) and make sure you have a model .bin Now When you added your model to your folder name your model name into mario_geo.bin or like luigi_geo.bin Make sure is in dynos folder
here are all the names for the playermodels and their caps
mario_geo.bin
marios_cap_geo.bin
marios_wing_cap_geo.bin
marios_metal_cap_geo.bin
marios_metal_wing_cap_geo.bin
luigi_geo.bin
luigis_cap_geo.bin
luigis_wing_cap_geo.bin
luigis_metal_cap_geo.bin
luigis_metal_wing_cap_geo.bin
toad_player_geo.bin
toads_cap_geo.bin
toads_wing_cap_geo.bin
toads_metal_cap_geo.bin
toads_metal_wing_cap_geo.bin
wario_geo.bin
warios_cap_geo.bin
warios_wing_cap_geo.bin
warios_metal_cap_geo.bin
warios_metal_wing_cap_geo.bin
waluigi_geo.bin
waluigis_cap_geo.bin
waluigis_wing_cap_geo.bin
waluigis_metal_cap_geo.bin
waluigis_metal_wing_cap_geo.bin
so first you need blender [to model ofc] and after youve done your model install fast 64 to convert some stuff and uhh export it and put it to a folder and put your model there and name the model "mario_geo.bin"