Where to add JavaScript in Impulse theme's step 4?

[Deoxes]

Hello,

I need help with Impulse codings, I found on youtube how I can add a quantity calculator.

My theme is Impulse, web: dehome.co.uk

Here telling need find global.js. But I cant find it, I found theme.js

I can’t find renderProductInfo and can’t find where I need add that code.

I will add all link how it’s telling add that code:

https://ed.codes/blogs/tutorials/display-variant-inventory-count-on-product-page-dawn-theme-no-app-shopify-2-0

The question is, where I need add Javascript in step:4

Thanks for help.