How to run program code from github?

Question

Crawling

It's not clear to me and it's not clearly written how to run the code. Not an accurate translation. Why call here? Where to put files? How to run files? What does the Depth parameter mean? What value to put in the Depth parameter?
https://github.com/derekchiang/Erlang-Web-Crawler

Answer 1

Why call here?

https://translate.google.ru/?hl=ru&tab=wT#view=hom...

Answer 2

call is not a call. It's a challenge. In fact - the launch of the method. How - you need to know Erlang.
Depth - I suspect that the parameter is responsible for the length of the chain of links that the crawler will follow. Roughly speaking - on page a there is a link to b, on page b - to page c. This is depth 3.
All other questions will be answered by the Erlang tutorial.