RossMitchell

My guess is that you are presently running a single site on commercial hosting that you subscribe to that is shared with other subscribers. Please advise if this is not your situation.

Assuming that you are using a shared hosting account, there will be a management control panel (most likely cPanel) where you manage and control various aspects of your website, things like email, FTP access, logs, databases, etc. Whatever you are using there will be a subscription plan behind it, a list of various limits and quotas that you are permitted to go up to, to increase any of these long term requires an upgrade to a more expensive plan.
Among the quotas which may be set are “subdomains” and “addon domains”, both of these give you the opportunity to run a different website under a different domain name.
Say you want to setup a testing website as a subdomain, say “dev.<yourDomainName>”, you would use the subdomain feature on the control panel to do this, it will ask you to set the directory which will default to being a subdirectory of “public_html”, just backspace over it and call it something.
You can then install WordPress.
The process is similar if you buy another domain name, in this case you would use the “addon domain” feature.
Your web hosting technical support people should be able to help you if required.

I created a child theme

when customizing css this is very helpful. However it is also possible to customize css using the customizer (admin bar > Customizer > Additional CSS)
These CSS changes are safe from website updates just like in your child theme. The customizer works so well that when you do not need to customize page templates, or need to customize your “functions.php”, that you may not need to use a child theme.

Suggest that you make your css more specific like this:
.site-title a {
since the title text is in a link, hence the “a” element.

Also suggest that you learn how to use your “web browser inspector” to see how your html and css are working.

Of course WordPress can as a platform host any style of browser application, easiest but not necessarily where the scripting is in PHP and Javascript, the database mySQL etc.
You could write yur own plugin that managed data in your own custom tables, or you could adapt an existing plugin (like woocommerce) to display and manage a catalog, it is a matter of your available skills and effort.

Easiest way I can think of to get WP to loop through all posts, is to hijack the page template mechanism, get the template from your theme that displays multiple posts, maybe the post archive template, rename it and adapt the loop to call your function, get WP to run your new page template and you will be very close to done.

Are you really sure that the database user and password are correct ?
Does this user have permissions on the database ALL permissions ?
Is there anything interesting in the error logs of your Apache and mySQL servers ?

Several things I would try:
– Enable debugging, details here:
https://codex.wordpress.org/Debugging_in_WordPress
– Look at the “net” tab of your browser inspector and load a page, see what takes the time.
– Examine the webserver logs

Good luck.

More specifically the “Feature Filter” tool there.

Seems that you will want “Translation Ready”, but will not need RTL, also get adsense support.

If you do buy a theme, please realise that they cannot be supported here as the volunteers don’t have access to the workings, so you will need to use the support forum of the vendor, pick one that is active and responsive, where people have had real answers recently, to questions you might see yourself asking.

I would think that this question would get a better response in the forum: “Developing with WordPress”

I have a favorite plugin that I use as a point of departure for developing several projects, it is a plugin that will load a SQL table from a csv file, which is not what you need at all. But you could readily change it so that it would upload a PDF to a nominated directory etc. When you do this PLEASE make sure that it cannot upload arbitrary file extensions, there is an old security “joke” plugin that would let you upload .php files, which you could then execute and take over the site. PLEASE don’t let this happen.

This plugin is:
https://wordpress.org/plugins/wp-csv-to-database/
please acknowledge the original author in your work.