Run the loop from a child theme?

Hi

I have made a child theme and I am pleased with that. Now I am trying to make a dynamic “static” start page.

The template is called gallery.php and I have included header and footer. In between I would like to make a custom loop. So first I tried with the loop from the themes index.php. That shows up in a weird way: header and one row with the title from my template and then the footer. I would like it to display all the posts as usual.

I am missing some fundamental knowledge to get this to work. I guess it has to do with wrong references, but I don’t know what to change or ad.