Hello
I havent fixed it, dont know where the button is at the moment. 
Topic summary
A user lost their “Add to cart” button on their product page in the Dawn theme.
After investigation, it was discovered the button still existed but had been renamed to “Buy now” during previous edits. The user had already changed the text back to “Add to cart” but wanted to modify the cart behavior.
Specific request:
- Remove the popup that appears when adding items to cart
- Show a simple “Product added to cart” message instead
- Allow checkout by clicking the cart icon at top right without the popup interruption
Solution provided:
Navigate to: Customize → Theme Settings → Cart → Select “Popup notification” in Cart type
This configuration successfully resolved the issue, giving the user their desired cart functionality.