Improve readme

Author: adinauer

sentry-opentelemetry/sentry-opentelemetry-agent/README.md

@@ -7,6 +7,17 @@ application by adding the following parameters to your `java` command:
 
 `$ SENTRY_PROPERTIES_FILE=sentry.properties java -javaagent:sentry-opentelemetry-agent.jar -jar your-application.jar`
 
+Your `sentry.properties` could look like this:
+
+```properties
+# NOTE: Replace the test DSN below with YOUR OWN DSN to see the events from this app in your Sentry project/dashboard
+dsn=https://[email protected]/5428563
+traces-sample-rate=1.0
+```
+
+For more details on configuring Sentry via `sentry.properties` please see the
+[docs page](https://docs.sentry.io/platforms/java/configuration/).
+
 As an alternative to the `SENTRY_PROPERTIES_FILE` environment variable you can provide individual
 settings as environment variables (e.g. `SENTRY_DSN=...`) or you may initialize `Sentry` inside
 your target application. If you do so, please make sure to set the `instrumenter` to `otel`, e.g.