Install on Shopify

In your Shopify admin, go to Online Store → Themes.
On your current theme, click ⋯ → Edit code.
Under Layout, open theme.liquid.
Find </body> near the bottom and paste your line just above it:

<script src="https://keyda.in/business/widget.js"
        data-key="kb_live_your_key_here" async></script>

Click Save, then open your storefront in a new tab.

Editing theme.liquid changes your live theme. If you would rather test first, Duplicate the theme, edit the copy, preview it, then publish.

What to train it on first

For a Shopify store, these earn their keep immediately:

Your shipping and delivery timelines
Your returns and exchange policy
Sizing or specification details
Which payment methods you accept, including cash on delivery

Upload them as documents or type them as saved answers. "Where is my order" is best handled by pointing customers to your order-status page in your fallback message — the assistant does not have access to individual orders.