Use SalesForce Lightning Platform REST API through .Net
Make New Connected app on Salesforce by:
Salesforce -> Setup -> home -> App Manager -> New Connected App [For more information about Conencted app: https://developer.salesforce.com/docs/atlas.en-us.api_rest.meta/api_rest/quickstart_oauth.htm]
you'll get your
• client_id as the Consumer Key
• client_secret as the Consumer Secret