products attribute problems

Hi to all,
i think is about theme compatibility, i cannot see any attributes values on the tab “additional information”, i set up “colors” and “sizes” but not value on select list, instead those tag are rendered:
https://ibb.co/f7mKzw
Even when I set “variable product” I cannot set those kind of attibutes.
If I choose “variable product” the button “add to cart” disappear too!

Im using this theme: https://www.cssigniter.com/themes/berliner/

how can i troubleshoot this kinds of problems? many thanks in advance!

Lapo