Quick Start Guide: https://cloud.google.com/vision/docs/quickstart-client-libraries
Setup the C# library using this command:
Install-Package Google.Cloud.Vision.V1 -Pre
NB: Setup the Create service account key
Remember to run this first:
gcloud auth application-default login
This will launch a browser prompting you to login - this will link to your billing account on Google Cloud
Follow instructions here: https://cloud.google.com/vision/docs/detecting-labels
Setup Google Cloud Project and authentication: https://cloud.google.com/vision/docs/labels
NB: Remember to install and initialize the Cloud SDK You'll also need to link to your Google Cloud Project during this process.