Put the YMAP file into: mods\update\x64\dlcpacks\miami_d3\dlc1.rpf\x64\levels\gta5\damn_work_metadata.rpf\
Use CodeWalker to edit the RPF file and add the provided YMAP in:
https://www.gta5-mods.com/tools/codewalker-gtav-interactive-3d-map