Plugin in widget

Text widget is for text; you need to be executing PHP code. You’ll probably want to write your own custom widget, or use something like this: https://www.ads-software.com/extend/plugins/php-code-widget/

I tried that plugin with the same result – it wont “print” anything :/ ??

I have no idea of how to write a custom widget?

Sounds like you need some very basic WordPress help; you can attempt to learn by reading the forums & general documentation, or just hire a developer to do it for you (i.e. from https://jobs.wordpress.net). In either case, these aren’t questions specific to my plugin (and even if they were, see FAQ101 – https://www.justin-klein.com/projects/facebook-photo-fetcher#faq101).