Place the ZIPMOD file inside on your mod folder. 
KOIKATSU\illusion\mods

patch notes:

2022-06-23: Release of mod
2022-06-26: Added Summer 2022 event accessories. Nonomi/Ayane/Wakamo/Koharu/Komakaze(Rabu)
2022-07-01: Added accessories for: Hina, Shiroko, Sumire.
2022-07-04: Changes fixes on students Halos Shaders / Added accessories: Atsuko, Arisu, Ayane, Hina, Hoshino, Iori, Nonomi, Serika, Shiroko.