API_TOKEN with Quarkus Telemetry Integration

When setting up Helios with Quarkus, you've asked to provide the following parameters:

quarkus.opentelemetry.tracer.exporter.otlp.endpoint=https://collector.heliosphere.io/traces
quarkus.opentelemetry.tracer.exporter.otlp.headers=Authorization=<API_TOKEN>

Where can I get this API_TOKEN? I've tried using the it was shown on Collector description, but with no luck.

Thanks in advance!