How can I change the icon's image in the header of Wishlist plus?

I want to replace the code, but I don’t know where to do it.

Create the code to enable Wishlist launch point using the image on the header menu. Save and view the changes.

<a href="#swym-wishlist" class="swym-wishlist">
  <img src="<<Replace With URL from Step 1>>">
</a>

Adding the Wishlist Plus Launch Point to your Shopify Site’s Header Menu - Swym

@Naru99 - wishlist icon usually is in header.liquid file, please check which file your theme is using and then you can add code above to that file to have yor own icon

Thank you for your reply.
My using theme is Dawn15.0.0.

I have checked many times, but I can’t find it in header likid file.