How can I access environment variables?

I am looking at this tutorial on the netlify site and it states that the value of a variable can be accessed by

const topSecretRecipe = process.env.MY_SECRET_SAUCE;

When I try this I get the error:

Uncaught ReferenceError: process is not defined at

I know that process is provided by node.js. Do I need to upload that to my Netlify app?

hi there @psionman ,

did you see this guide already? this might be a good place to start:

if you still have questions afterward, do let us know what you tried and we can assist.