How to force a Custom Post Type template by filename

you likely need to do a flush re-write. go to settings/permalinks in the dashboard and click save. You’ll be good to go. In the future you can add this directly to your CPT plugin. I would suggest getting a bit more creative with your naming though so you don’t have conflicts later.

MariaDB version not recognised

As discussed in comments, the problem was a missing prce2 package which meant preg_match(), used by $wpdb->db_version() to parse the MySQL version number out of SELECT VERSION(), didn’t work. Solved by sudo yum install pcre2

Newbie question – which css file to edit

You generally shouldn’t edit your theme’s CSS files if the theme isn’t one you authored yourself. The reason is that these changes would be lost if you ever updated the theme. The two recommended ways of adding CSS of your own are: Go to Appearance > Customize > Additional CSS and add your CSS here. … Read more

Why do all links on my WordPress site show me the homepage?

It looks like you’ve constructed an URL relative to the template PHP you’re rendering, i.e. this code is in wp-content/themes/mycustom/index.php you want to load wp-content/themes/mycustom/admin/dashboard.php => relative URL is admin/dashboard.php? That’s not correct. URLs are relative to the URL the user is currently on in their browser, which may be /, or /category/post-slug, or /year/month/post-slug, … Read more