These instructions guide you to locate the client ID and client secret that is necessary to authenticate using credentials.
Go to Setup > Apps > App Manage.
Select New Connected App.
The steps may vary depending on the version of Salesforce you are running. In Spring 19 classic UI: Setup > Build > Create > Apps > Connected Apps > New.
Navigate to Setup > Build > Create (Apps), and validate all your connected apps:
Select your app name to go to the page where you can view and manage all information about your connected app.
Write down or copy your Consumer Key (client_id) and Consumer Secret (client_secret).
For secure account access, get a Salesforce Security Token. If you don’t have a security token, go to Account > Settings > Reset My Security Token and select Reset Security Token. You’ll receive your Security Token by email.
In Spring 19 classic UI: My account > My Settings > Personal > Reset My Security Token.