Add training guide link in readme

README.md

@@ -116,4 +116,7 @@ from towhee import ops
 op = ops.audio_embedding.nnfp(device='cpu').get_op()
 op.save_model('onnx', 'test.onnx')
 ```
-    PosixPath('/Home/.towhee/operators/audio-embedding/nnfp/main/test.onnx')
+    PosixPath('/Home/.towhee/operators/audio-embedding/nnfp/main/test.onnx')
+
+## Fine-tune
+To fine-tune this operator, please refer to [this example guide](https://github.com/towhee-io/examples/blob/main/fine_tune/7_fine_tune_audio_embedding_operator.ipynb).