we are normally using some codes of repository on github.
But if the tree structure of project is complex, then it is difficult codes of files.
So, you can install a chrome extension (OctoTree). it is providing a repository tree structure in left side.
So, you can simply go to files that you want.
https://chrome.google.com/webstore/detail/octotree/bkhaagjahfmjljalopjnoealnfndnagc
