NOTE : First of all install OpenIV and SxripthookV
Before these all download and install gameconfig and heap adjuster to avoid crashing...
1 - Start OpenIV and click in GTA V windows (Case it asks for game location, set it).
2 - Click in Tools > ASI Manager, make sure that OpenIV.asi and ASI Loader are installed:
3 - Click in Tools > Package Installer:
4 - Select the .OIV file and click in Open:
5 - A window similar to this one should appear, click in Install:
6 - Now OpenIV will ask if you want install in mods folder or in original game files, i recommend to *choose mods folder option to make easier disable the mods when going to play online (*Some mods don't edit RPF files, in this case the "mods folder" option will be disabled):
7 - If everything goes well you should see the "Installing" screen and after some time the "Installation Succeed" screen, the installation time may be longer depending on what RPF files OpenIV will need to handle :)