To get to Vice City in-game, go to the east coast of the game world by boat or plane. Keep driving or flying east of Humane Labs until you reach Vice City. The story from the original game is unfortunately not available, but the modders have added some missions themselves.
The modding tool is used for installation OpenIV needed. After you look over the mod our download downloaded and unpacked the file, you must insert the ViceCryRemastered.oiv file in the main directory of GTA 5. The mod can then be installed. The developers recommend a fresh installation of the main game, otherwise problems could arise.