Installing Mods with OpenIV
Install OpenIV. After you installed OpenIV, start it. Click on GTA V, then choose your GTA V folder. Now go to "Tools", then click on "ASI Manager" and install everything there.
Now you can install every .oiv file with just a few clicks. To install a .oiv file, go to "Tools", then click on "Package Installer" and choose the .oiv file. I would recommend using the Mods folder.
Watch this video if you couldn't install OpenIV / How to install OpenIV
Installing SkripthookV & SkripthookVDotNet
You have to install SkripthookV & SkripthookVDotNet.
After you installed SkripthookV and SkripthookVDotNet, you must create a folder in your root GTA V folder and call it "scripts". Drag the scripts into the "scripts" folder. And then you are done!
You should watch this video if you couldn't understand how to install SkripthookV & SkripthookVDotNet / How to install SkripthookV & SkripthookVDotNet