add explanation to the app page

app.py

@@ -278,8 +278,9 @@ with gr.Blocks() as demo:
     user_answers = gr.State(value=[])
 
     with gr.Row(variant="compact"):
-        gr.Markdown(f"## Welcome to the {EXAM_DATASET_ID} Quiz")
-    with gr.Row(variant="compact"):
+        gr.Markdown(f"## Welcome to the smolagents code reviewer")
+        gr.Markdown("This application will review your smolagents code, and provide feedback on your solutions.")
+        gr.Markdown("This exercise is not reviewed or certified! It's about trying out smolagents for the first time.")
         gr.Markdown(
             "Log in first, then click 'Start' to begin. Complete each coding challenge "
             "and click 'Next' to proceed. You'll get feedback on your solutions at the end."