adding readme instructions

examples/testing-context-propagation/automatic-instrumentation/README.md

@@ -2,19 +2,40 @@
 
 ### Overview
 
-TBD
+This example demonstrates how to test context propagation with automatic instrumentation. It consists of a simple application that uses a backend service to store data. The application is instrumented with OpenTelemetry and sends traces to an Jaeger backend. 
+
+```mermaid
+graph LR
+  User -- POST /sendData --> ServiceA
+  ServiceA -- POST /augmentData --> ServiceB
+```
 
 ### Requirements
 
-- Docker
-- Tracetest CLI
+To run it you need:
+
+- [Docker](https://www.docker.com/get-started/)
+- [Tracetest CLI](https://docs.tracetest.io/getting-started/overview)
+
+You will need to have a Tracetest.io account and an environment to run this example. Once that you created it, add an `.env` file with the following content:
+
+```bash
+TRACETEST_ENVIRONMENT_ID=...
+TRACETEST_API_KEY=...
+```
+
+You can get the values for both `TRACETEST_ENVIRONMENT_ID` and `TRACETEST_API_KEY` on the page: https://app.tracetest.io/retrieve-token
 
 ### Running the Example
 
+After setting up the environment, you can run the example with the following commands:
+
 ```bash
 docker compose up
 ```
 
+And to run the test you can execute the following commands: 
+
 ```bash
 tracetest configure ## connect to your environment