update readme

README.md

@@ -80,6 +80,24 @@ For each video, We hire workers to annotate ten shortened video summaries.
 }
 ```
 
+### File Structure of Dataset
+The file structure of VideoXum looks like:
+```
+dataset
+└── ActivityNet
+    ├── anno
+    │   ├── test_videoxum.json
+    │   ├── train_videoxum.json
+    │   └── val_videoxum.json
+    └── feat
+        ├── blip
+        │   ├── v_00Dk03Jr70M.npz
+        │   └── ...
+        └── vt_clipscore
+            ├── v_00Dk03Jr70M.npz
+            └── ...
+```
+
 
 ## Citation