add readme

app.py

@@ -350,8 +350,19 @@ def seg_track_app():
         gr.Markdown(
             '''
             <div style="text-align:center;">
-                <span style="font-size:3em; font-weight:bold;">SAM2</span>
+                <span style="font-size:3em; font-weight:bold;">SAM2 for Video Segmentation 🔥</span>
             </div>
+            This API supports using box (generated by scribble) and point prompts for video segmentation with SAM2.
+
+            1. Upload video file 
+            2. Select mdoel size and downsample frame rate and run `Preprocess`
+            3. Use `Stroke to Box Prompt` to draw box on the first frame or `Point Prompt` to click on the first frame. 
+               Note: The bounding rectangle of the stroke should be able to conver the segmentation target.
+            4. Click `Segment` to get the segmentation result
+            5. Click `Add New Object` to add new object
+            6. Click `Start Tracking` to track objects in the video
+            7. Click `Reset` to reset the app
+            8. Download the video with segmentation results
             '''
         )
 
@@ -409,7 +420,7 @@ def seg_track_app():
                             value=0.0,
                         )
                         new_object_button = gr.Button(
-                            value="Add new object", 
+                            value="Add New Object", 
                             interactive=True
                         )
                         track_for_video = gr.Button(