Click the Copy button on the "Dynamic CSS" tab. Go to the section file in your Shopify code editor where you want the button and paste it below or above all the code.

Copy the code from the Schema tab. Go to the Section file where you want the button (e.g. image-banner.liquid) and paste inside the "settings": [ ... ] block.

Copy the Liquid HTML code. Paste it in your Section file where you want the button to appear. It will automatically use the settings you added in Step 2.