Clarify env variables vs. parameters

live_exam_os/README.md

@@ -91,6 +91,11 @@ export CACHE_FS="cache"
 ```
 Uncomment and set the necessary variables to customize your build environment.
 
+
+### Environment Variables vs. Parameters
+
+The parameters passed to the script simply set environment variables. You have the choice between directly using environment variables or using the parameters. This flexibility allows you to configure the build environment either through a .env file or by passing parameters directly to the script.
+
 ### Example Usage
 
 Here are some examples of how to use the script with the Makefile: