You must create a new Cloud Manager API Integration in your adobe io console.
Use the following documentation to create a new integration:
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<a href="https://www.adobe.io/apis/experiencecloud/cloud-manager/docs.html#!AdobeDocs/cloudmanager-api-docs/master/create-api-integration.md">Cloud Manager Documentation</a>
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Once you've created the integration, you'll be able to copy paste the values into this form and test your connection.
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There also this Adobe IO documentation on creating Service Accounts (if the docs above are not sufficient).
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<a href="https://www.adobe.io/authentication/auth-methods.html#!AdobeDocs/adobeio-auth/master/AuthenticationOverview/ServiceAccountIntegration.md">Adobe IO Documentation for creating a service account</a>