Hello marcoluca1988,
Thank you so much for using our theme Mercantile. If you want to change the default text of slider, and blog section you can either customize the theme code or you can use the premium version of it. In the premium version, you have lots of added features. If you want to change it on free theme, find the codes inside the acmethemes/hooks/slider-selection.php file and check other needed files as well.
We are offering 40% discount on all our products now. You can use that offers as well.
Regards
Acme Supports