1. Open chrome and click chrome menu
2. Now scroll page till end and click on Advance
3. After clicking on advance page will expand and click on ‘open your computer proxy’
As per your system means it is Mac or Window, it will open respective screen. For window it look like this
If you’re using a Mac, you can visit their official support website for more details on how to finish up your proxy setup. And if you’re using Windows, check this article out for a simple explanation on how to set it up.