If you want to start the game from the beginning, you can simply click New Game in the game's main menu:

However, this will overwrite your current progress. Far Cry 5 has one save slot available and your new game will autosave any progress you make into it.
If you decide to restart, the following will reset:
However, your new savegame will retain:
• Silver Bars
• Items purchased with Silver Bars
• Live Event rewards
• Ubisoft Connect rewards
• Additional content such as ULCs you unlocked
If you'd like to keep the progress from your previous game, we recommend that you make a backup of your save data in a different location before you start a new game.
To backup your savegame:
PC If you have any other questions, please get in touch.
However, this will overwrite your current progress. Far Cry 5 has one save slot available and your new game will autosave any progress you make into it.
If you decide to restart, the following will reset:
However, your new savegame will retain:
• Silver Bars
• Items purchased with Silver Bars
• Live Event rewards
• Ubisoft Connect rewards
• Additional content such as ULCs you unlocked
If you'd like to keep the progress from your previous game, we recommend that you make a backup of your save data in a different location before you start a new game.
To backup your savegame:
PC
• Open the savegame directory
• Select the file and copy it into a different location, for example on your desktop.
• Select the file and copy it into a different location, for example on your desktop.
PS4
• Refer to Sony's guide on backing up your save game on a USB stick.