GGO V (previously GGOHud) is a mod for Grand Theft Auto V that adds a couple of features from the Gun Gale Online VRMMO in Sword Art Online:
Please note that you need to install LemonUI and PlayerCompanion for GGOV to work.
First, drag and drop all of the files inside of the 7zip into your scripts directory. Then, open the MANUAL INSTALL directory and copy those ytd files to mods\update\update.rpf\x64\textures\script_txds.rpf.
After installing the mod, you will see the Squad Members and Player Information HUD elements. You can open the inventory by pressing Tab/R1/RB/R.
There is a menu that you can use to configure some options. This menu can be opened by entering ggo in the cheat input field.
For adding weapons and modifying other options, please check the wiki.