You can install most of this mod manually, but you will not get the full experience. I highly recommend using the .oiv file.

1. Drop popgroups.ymt into mods/update/update.rpf/x64/levels/gta5
2. Drop popcycle.dat into mods/update/update.rpf/common/data/levels/gta5
3. Drop dispatch.meta into mods/update/update.rpf/common/data
4. Drop vehiclemodelsets.meta & loadouts.meta into mods/update/update.rpf/common/data/ai
5. Drop setelegen folder into mods/update/x64/dlcpacks
6. Add the line "<Item>dlcpacks:/setelegen/</Item>" into dlclist.xml in mods/update/update.rpf/common/data