Where are the training datasets for "file://path_to_file/train" for Chapter 6 "ctr.py"?

When running the line of code: 

`df = spark.read.csv("file://path_to_file/train", schema=schema, header=True)`

There are no clear instructions provided for downloading the training datasets into a designated folder path. Would you like to clarify if there is a link to the custom schema for the click log data?

Thank you in advance,
Best wishes,

Haocheng