Instructions on using save files for Assassin's Creed IV Black Flag:
1. Download desired Assassin's Creed 4 save game file to your desktop.
2. Extract it using WinZip or any similar tool. Select extracted files, right click, and choose "Copy".
3. Navigate to Assassin's Creed IV save location and pase previously copied files here.
4. Start the game and your save status will be loaded automatically.
For brand new game installation:
If you have a brand new game installation
(which means you didn't play game before using downloaded savegame), it is recommended to start the game, and exit right after the first mission starts.
Do it before following the instructions above. This method will create necessary files within the game save directory.