To get it to work, you need to download a converter tool and own a copy of GTA 5 and GTA 4 on PC (the mod converts Liberty City from GTA 4 into your copy of GTA 5). The idea is you can fly between the regular Los Santos map and GTA 4's Liberty City map. You can see how this looks in the teaser video, below. The mod is the work of the people behind modding tool OpenIV, who said in a post on GTAForums that Liberty City will not replace Los Santos or Blaine County, but will appear across the sea. Liberty City is a fictional recreation of New York, and was the setting for Grand Theft Auto 3 and 4. A group of ambitious modders are working to put Liberty City inside Grand Theft Auto 5.
