When you purchase a Venice license from ThemeForest & download the theme package, you will receive a zipped file. Unzip this file and find "venice.zip" file. DO NOT UNZIP IT!
Within your WordPress Dashboard, navigate to Appearance > Themes:
Click the "Add New" button at the top-left of the page > Click the "Upload Theme" button at the top. Click "Choose File" > find your zipped "venice.zip" file > Click the "Install Now" button:
Once the theme is successfully installed on your WordPress, you can "Activate" it via the installation page or via Appearance > Themes to switch over and begin using your Venice theme!