Follow the on-screen instructions. You might be prompted to choose your language and then accept the terms of the license agreement.
Do you have the or a downloaded .exe ?
: When prompted, enter your serial number. Authentication Code : sony vegas pro 11 serial key and authentication code install
You can find the official Sony Vegas Pro 11 installer from trusted sources like the Internet Archive or old software repositories if the official site no longer hosts it. Verify file hashes if possible. Follow the on-screen instructions