Login to https://portal.azure.com and create a new Speech Service. After that, copy the generated key and endpoint.
After publishing this app, open module detail page of this app on Service Center and configure AzureSubscriptionKey and RecognitionLanguage site properties. Key is the one you copied at the previous step.
Open Integrations in module detail page of Service Center. And modify the endpoint of Consumed REST APIs to the one you copied at the step 1. Note that the last / character is not necessary.