Right-click part1.rar and select "Extract Here." The software will automatically pull data from the other parts to recreate the full installer.
Large games like Assassin's Creed are often split into multiple parts (e.g., part1.rar , part2.rar ) to make downloading easier. telechargement-assassins-creed-part1-rar
You generally cannot open part1 alone. You must have all subsequent parts (part2, part3, etc.) in the same folder. Right-click part1