First, you need to disable the BattlEye anti-cheat in the Rockstar Game Launcher. After that, reinstall LSPDFR if you already have it. Then, download the LSPDFR Manual. Once you've downloaded it, move the files from the archive to the game's root folder, replacing the existing ones.
https://www.dev-c.com/gtav/scripthookv/ Updated ScriptHook V