This website is themed like a terminal, so you use classic terminal commands for navigation:
ls or dir to list the contents of directory
cd [folder] to move to a [folder]. If you don't supply any argument, you'll move back to the start of the website
read [filename] to read files. If the file isn't readable, it will be downloaded (like a .zip for example)
Pro tip: you don't have to type out the full name of the file, you can just type only a part and if the website can recognise which file in the directory you mean, it will be displayed!

user@web: ~ $