Installation: 
If you havent already, download and install the latest version of ScriptHook RDR2: http://www.dev-c.com/rdr2/scripthookrdr2/
Then download and install the latest version of Lenny's Mod Loader: https://www.rdr2mods.com/downloads/rdr2/tools/76-lennys-mod-loader-rdr/
Now drag the lml folder to your RDR2 directory.
Pretty much it, enjoy.