Widget on New Page Sidebar

[mauri_mono]

I have created a page on my site where all products are shown. That same page has a left sidebar. How can I put a widget on that sidebar that shows a filter of all categories and a reset button?
I mean, if I create a widget, after "Specified Page" the page I created does not appear in the dropdown field.

[Rahul Gupta]

@mauri_mono Have you created the CMS page.

Because there we can see only the CMS page option.

Thanks