First of all opem OpenIV and go trough mods/x64f.rpf/levels/gta5/props/roadside/v_signs.rpf and drop the prop and the texture there

For Ymap installation: 

Be sure to have ymap installed correctly: https://www.gta5-mods.com/tools/mapeditor-2-ymap-converter

Go trough mods/update/x64/dlcpacks/custom_maps/dlc.rpf/x64/levels/gta5/_citye/maps/custom_maps.rpf and drop the xml file from ymap folder

For MapEditor installtion:

Also be sure to have MapEdiotr correctly installed: https://www.gta5-mods.com/scripts/map-editor

Just drop the XML file intro your Gta5 directory folder and when in game press the load map button and search for RadarIT file 

Enjoy!