Update demo content

Author: sergioburdisso

demo.md

@@ -1,3 +1,9 @@
-## Demonstration Video
+# EACL 2026 - System Demonstration Video
 
-[![IMAGE ALT TEXT HERE](https://img.youtube.com/vi/YOUTUBE_VIDEO_ID_HERE/0.jpg)](https://www.youtube.com/watch?v=YOUTUBE_VIDEO_ID_HERE)
+The demo illustrates the key capabilities of th SDialog toolkit through a practical examples following a simple call-center use case, showing how SDialog enables researchers to build, benchmark, and analyze conversational AI systems systematically, from initial agent design through dialog generation to comprehensive evaluation.
+
+**(Click the image below to watch the demonstration video)**
+
+[![SDialog System Demo Video](https://img.youtube.com/vi/oG_jJuU255I/0.jpg)](https://www.youtube.com/watch?v=oG_jJuU255I)
+
+Alternatively, link to the video: https://www.youtube.com/watch?v=oG_jJuU255I