Update readme

Author: fmazmz

.env.example

@@ -0,0 +1,2 @@
+NTFY_BASE_URL=https://ntfy.sh
+NTFY_TOPIC= //Add your topic here

README.md

@@ -11,8 +11,20 @@ A JavaFX-based chat client using [ntfy](https://docs.ntfy.sh/) for backend messa
 - Unit tests for `Model` class
 - (Advanced) Send files via "Attach local file" option
 
-## 🚀 Run Instructions
-1. Set `JAVA_HOME` to JDK 25
+
+## Requirements
+
+- **Java**
+    - **Version**: `25`
+
+- **Maven Compiler Plugin**
+    - **Version**: `3.11.0`
+    - **Configuration**:
+        - **Release**: `25`
+
+## Usage
+1. Set `JAVA_HOME` to JDK 25.
+2. Create a **.env** file with the required variables. You can also clone and fill **.env.example** and rename it to `.env`.
 2. Start with:
    ```bash
    ./mvnw clean javafx:run