There are three methods for installing snippets.
Quick and Dirty
Copy the “raw” version of the snippet to your theme’s functions.php file.
Less Quick but Better
Use a snippet manage plugin (like Code Snippets) to install and manage the snippet.
Create a simple, site-specific plugin for the snippet(s). Full walk-through here.
If you run into any issues installing a snippet, make sure to check out our Snippet Troubleshooting Guide.