PHP code snippet for embedding gallery in source files

Hi there, I have tried to put a gallery code into a text widget, but this doesn′t work and just shows up as code on the page.

I wonder if you could help me out with a PHP code snippet to embed directly into the code of the page where I want this particular gallery?

Much appreciated. ??

https://www.ads-software.com/extend/plugins/gallery-without-the-fluff/