docs: add tutorials of fine-tune on a custom dataset (#711)

Author: XixinYang

benchmark_results.md

@@ -1,13 +1,5 @@
 This folder contains examples for various tasks, which users can run easily.
 
-### Finetune
-```
-python examples/finetune.py
-
-```
-This example shows how to finetune a pretrained model on your own dataset. You can also specifiy `--freeze_backbone` to choose whether to freeze the backbone and finetune the classifier head only.
-
-
 ### Single process with model training and evaluation
 ```
 python examples/train_with_func_example.py

docs/en/how_to_guides/finetune_with_a_custom_dataset.md

@@ -0,0 +1,17 @@
+This folder contains scripts for fine-tuning on your own custom dataset, do refer to [tutorials](https://mindspore-lab.github.io/mindcv/how_to_guides/finetune_with_a_custom_dataset/) for details.
+
+### split_files.py
+```shell
+python examples/finetune/split_files.py
+```
+This file taking Aircraft dataset as an example, shows how to manually reorganize data into a tree-structure directory according to an annotation file. Note that it's only for Aircraft dataset but not a general one, you'd better check the content before running it.
+
+### read_images_online.py
+
+This is an example demonstrating how to read the raw images as well as the labels into a `GeneratorDataset` object, which is a `MappableDataset` class that can be read directly by models. You are recommended to insert this part into your data preprocessing script or training script, but not run it alone.
+
+### finetune.py
+```shell
+python examples/finetune/finetune.py --config=./configs/mobilenetv3/mobilnet_v3_small_ascend.yaml
+```
+A script for fine-tuning with some example code of fine-tuning methods in it (refer to the tutorial mentioned above).