Run the following command to install the extension into your codebase:
$ composer require example_package/example_processor
By default, ApiOpenStudio uses assumes that processors are within the ApiOpenStudio namespace and uses only ther the machine_name of a processors to find it:
ApiOpenStudio\{processor,security,output,exndpoint}\<machine_name>
However, in the case of 3rd party extensions, it will have its own namespace and classname. So instead of the machine name, you need to use the full namespacing in your resource YAML files. The maintainer should have already set that for you in the machineName
attribute, e.g.
processor: ExtensionNamespace\ExtensionName
...