Log in at http://www.web.de with your web access data and click on Domains to open the WebBaukasten and then the editor.
Call up "Pages" (A) and select the page or sub-page (B) on which you want to integrate your bookingkit on your website. Then click on "Open page" (C) and you will be redirected to the corresponding page of your homepage.
Call up "Modules" (A) in the editor and then drag and drop "Script" (B) into the page-specific area (in the preview).
At this point, a field opens in which you can insert the 2-line code for your bookingkit.
You can call up this code (C) in your account under "Marketing" (A) -> "Own website" (B):
Finally, click on "Publish" to integrate your bookingkit on your website. Please note that bookingkit is not displayed in the preview, but has nevertheless been implemented on your website.