Once clicked the copy button, you paste the widget to the module Widget/HTML of your website.
It is important to use the module Widget/HTML because the custom elements here will overwrite the default Jimdo system styles.
Please note that some widgets are not available in preview in edit mode but will be correctly displayed in view mode (fullwidth sections)
To change the image, you need to upload your own image to Design> Custom> Custom
Template> Files. Once uploaded, click the image name which will be opened in a new tab and copy the url of the image from the browser address bar:
Paste it inside the module Widget/HTML replacing the default image of demo site:
<img src="https://u.jimcdn.com/cms/o/s1aeecbbb2a5865b1/userlayout/img/tile09.jpg" alt="" />