message: Updated dcn2nodes/README.md accordingly
diff: A sample of building and training Deep & Cross Network with HugeCTR on multi-nodes [(link)](https://arxiv.org/pdf/1708.05123.pdf).
  ## Dataset and preprocess ##
  -The data is provided by CriteoLabs (http://labs.criteo.com/2014/02/kaggle-display-advertising-challenge-dataset/). The original training set contains 45,840,617 examples. Each example contains a label (1 if the ad was clicked, otherwise 0) and 39 features (13 integer features and 26 categorical features). The original test set doesn't contain labels, so it's not used.
  +The data is provided by CriteoLabs (http://labs.criteo.com/2014/02/kaggle-display-advertising-challenge-dataset/).
  +The original training set contains 45,840,617 examples.
  +Each example contains a label (1 if the ad was clicked, otherwise 0) and 39 features (13 integer features and 26 categorical features).
  +Because the original test set doesn't contain labels, it is not used.
  +
  +### Requirements ###
  +Python >= 3.6.9
  +Pandas 1.0.1
  +Sklearn 0.22.1
  1. Download the dataset and preprocess
  -Go to [(link)](http://labs.criteo.com/2014/02/kaggle-display-advertising-challenge-dataset/) and download kaggle-display dataset into the folder "${project_home}/tools/criteo_script/".
  +Go to [(link)](http://labs.criteo.com/2014/02/kaggle-display-advertising-challenge-dataset/)
  +and download kaggle-display dataset into the folder "${project_home}/tools/criteo_script/".
  ```shell
  -$ cd ../../tools/criteo_script/ && bash usage.sh && cd ../../samples/dcn2nodes/
  +$ cd ../../tools/criteo_script/
  +$ bash preprocess.sh dcn 1 0
  +$ cd ../../samples/dcn/
  ```
  -2. Translate the dataset to HugeCTR format
  +2. Convert the dataset to HugeCTR format
  ```shell
  $ cp ../../build/bin/criteo2hugectr ./
  -$ ./criteo2hugectr ../../tools/criteo_script/train.out criteo/sparse_embedding file_list.txt
  -$ ./criteo2hugectr ../../tools/criteo_script/test.out criteo_test/sparse_embedding file_list_test.txt
  +$ ./criteo2hugectr ../../tools/criteo_script/train. criteo/sparse_embedding file_list.txt
  +$ ./criteo2hugectr ../../tools/criteo_script/val criteo_test/sparse_embedding file_list_test.txt
  ```
  ## Plan file generation ##
  