update progress bar

app.py

@@ -460,6 +460,7 @@ with gr.Blocks(css=CSS, theme=gr.themes.Soft(text_size=sizes.text_md)) as demo:
         [vectordb, msg, num_context, img_context, chatbot, hf_token, model_path],
         [chatbot, references, ret_images],
     )
+    documents.change(lambda: "<h1 style='text-align: center'>Click the 'Extract' button to extract data from PDFs<h1>", None, prog)
 
     back_p1.click(lambda: gr.Tabs(selected=0), None, tabs)