I found a thread here which told me how to show an url in a iFrame on my dashboard. I used the example flow there :).
This works fine, but I only find a way with fixed height and width. I wanted to use all availabe space on my screen. And this is different. Depending on the device. Also, if possible I want to support different url's to the template.
Searching for this problem is something for a specialist. I don't know html, css,... So can someone please help me with a example flow or the tags I have to use.
And the iFrame is always too small:
