Remove page title from single page

From the searching I’ve done, it looks like normally you’d be able to use CSS to remove the title from a single page like this:

#post-THEPOSTID .entry-title {display: none; }

And “THEPOSTID” is normally found in the body tag HTML, but it’s not in the particular theme that I’m using for this site (Boldy).

I added the plugin “Reveal IDs”, so I found the page ID that way.

I searched all over the page’s rendered HTML and in the HTML Inspector, but cannot find any page-specific identifying ID number, so using CSS is out (at least CSS that uses the page’s ID). So it looks like I’ll have to do this in code.

That’s fine, but I’m having four problems – all due to my lack of knowledge in that area:
1) Precisely what php page do I need to put in my child theme folder
2) How do I properly include that file in my child theme (do I need to do something in the functions.php file similar to how I’m using the custom CSS file in my child theme?)
3) What exactly is the code I need to use to conditionally omit the title of that one page
4) Can I use the page id, since I know it from the plugin, or should I use the page’s name?