Here is a detailed tutorial on how to install a custom map and stream it in your server as a resource:
Download the .xml file from the Website that your linked
Download https://www.gta5-mods.com/tools/mapeditor-2-ymap-converter
Then open the MenyooToYMAP program and Import the file .xml and export it. it will save your file as a .ymap.xml
Then you need to open OPEN IV http://openiv.com/
Create an Archive .rpc (I believe it’s in the top bar, under FILE > Create Archive > then create the .rpf file and save it anywhere u want (u will delete it after).
Then you drag the already converted file (ymap.xml) to OPEN IV; and you will have a clear ymap
That’s how you do that