How do I apply a template to a new page?

I created a custom template called page_custom.php. It’s exactly the same as page.php except it has <h1>Custom template</h1> at the top (just to see if it’s working for now). I added this file to the my theme’s folder, but I can’t figure out how to apply it to a page in the wordpress admin. If I name change the name of the file to page-hours.php, my hours page shows the custom template. However, I want to be able to apply this template to multiple pages, and I don’t see the option where to give a page a template when creating it.

Here is a screenshot of all the options I see when creating a new page. I don’t see any area for assigning a template.

View post on imgur.com