to install the props you must download addonprops just check for it on gta5 mods.com
after you do go to:
mods/update/x64/dlcpacks/addonprops/dlc.rpf/props.rpf
then just drag and drop.
NOTHICED THAT-
if you have some other addonprops you want to use with the map then it wont load both of them,
and the reason to that is the def_props so if you want to use both so you need to do something
a bit hard, you have to add ALL the props to addonprops editor incolde the one you want to use with
or just replace the one you want to use.