Add Cart Icon to Custom Shopify Header

URGENT - I want someone who's expert in javascript and console reading. I have coded a custom shopify header and I wish to add theme's cart icon and its drawer functionality to my custom header.
Im attaching the theme export file below.

Im using Kalles theme and added a custom-header1.liquid section

Requirements:
- Experience with Shopify and the Kalles theme
- Proficiency in JavaScript
- Ability to read and debug console errors

I've attached the theme export file for reference.