[FileBasedConfiguration] Resource Documentation

docs/file-based-configuration.md

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+# File-based Configuration
+
+> **Status:** [Experimental](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/versioning-and-stability.md)
+> For more information about the OpenTelemetry configuration specification, see:
+> **[File-based configuration documentation](https://opentelemetry.io/docs/specs/otel/configuration/sdk/)**  
+
+You can configure OpenTelemetry using a YAML file. This method is disabled
+by default and must be explicitly enabled.
+
+To enable file-based configuration, set the following environment variable:
+
+```bash
+OTEL_EXPERIMENTAL_FILE_BASED_CONFIGURATION_ENABLED=true
+```
+
+By default, the value is false.
+
+You can also specify the configuration file path (default: config.yaml):
+
+```bash
+OTEL_EXPERIMENTAL_CONFIG_FILE=/path/to/config.yaml
+```
+
+In your config file you can use environment variables in the format `${ENVIRONMENT_VARIABLE}`
+instead of a fixed value.
+
+You can also use `${ENVIRONMENT_VARIABLE:-value}`, where `value` is the fallback
+if the environment variable is empty or not set.
+
+## Configuration Examples
+
+### Resource Configuration
+
+You can configure resource attributes directly in YAML or via the
+`OTEL_RESOURCE_ATTRIBUTES` environment variable.
+
+``` yaml
+resource:
+  # Configure resource attributes. Entries have higher priority than entries from .resource.attributes_list.
+  # Entries must contain .name and .value
+  attributes:
+    - name: service.name
+      value: unknown_service
+  # Alternatively, configure via a comma-separated list (same format as OTEL_RESOURCE_ATTRIBUTES).
+  attributes_list: ${OTEL_RESOURCE_ATTRIBUTES}
+```  
+
+### Resource Detectors Configuration
+
+For more details and updates, see: [Resource Detectors list and documentation](https://opentelemetry.io/docs/zero-code/dotnet/configuration/#resource-detectors)
+
+``` yaml
+resource:
+  detection/development:
+    detectors:
+      azureappservice: # Detects Azure App Service resource information
+      container:       # Detects container resource info (container.* attributes) [Core only]
+      host:            # Detects host resource info (host.* attributes)
+      operatingsystem: # Detects OS-level attributes (os.*)
+      process:         # Detects process-level attributes (process.*)
+      processruntime:  # Detects process runtime attributes (process.runtime.*)
+      service:         # Detects service.name and service.instance.id
+```