Your organization's API tokens can be found under the API Tokens tab in Organization Settings.
The service key (used for APM) is comprised of a write-enabled token and the name of the instrumented service and takes the format of <api-token>:<service-name>.
When the APM Integrated Experience is enabled, AppOptics shares a common navigation and enhanced feature set with the other integrated experiences' products. How you navigate the product and access its features may vary from these instructions. For more information, go to the APM Integrated Experience documentation.