In order to configure and use auvious speech to text capabilities you must configure Google Cloud speech to text, use a service account and download the generated json key file for your organization. Detailed documentation can be found here.
Configuration of a google cloud project
In case that it's the first time you create a Google project you can follow this guide in order to enable google cloud speech to text managed service.
Service account creation and production of json key file
Follow the steps for creating a service account from this guide.
After you have configured speech to text service account you can follow these instructions to generate and download the neccesary json key file that contains the authorization parameters of your organization google speech to text service.
Optional configure quota and limits for Google speech to text service account
In case that your organization needs to limit the use of speech recognition in order to calculate and never pass the cost of your organization's budget, you can follow this guide to set up the limits of the service.
Prices and cost calculation of Google speech to text service can be found here.