You need to purchase and download AI plugins from MAGIX from the official website or any other authorized source. Once downloaded, install the plugins by following the instructions provided with the package.
After installation, open Vegas Pro 16.
Go to Vegas Pro 16 settings and specify the path to the folder where your new plugins are located.
Restart Vegas Pro 16. Once downloaded, you will be able to use the new AI plugins in your projects in Vegas Pro 16. They should appear in the list of available effects and tools.