I'm stuck in a basic Mongodb php tutorial

I was following this tutorial : http://pronewb.com/mongodb-as-in-humongous-not-retar开发者_C百科ded. All was well until the "I feel the vibe" section. I do not know where to begin this section. Do i have to create a new php file or type it in some command line?

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The code in that section, and following ones, is PHP code so yes it should be in a PHP file.

Note that the pieces of code presented are demonstrations of the syntax and usage, rather than snippets that you can expect to copy/paste and execute on their own.