Adding wordpress files to existing site domain folder

Hi

I hope someone can help.
I have successfully installed WordPress onto my Mac Mini. It is being used as a web server, hosting a couple of websites already. They are being hosted within the www folder, using the ‘Personal Web Sharing’ function.

I am able to work on/view my WordPress site locally using MAMP. The problem I am now having is trying to workout how I go from viewing my site locally to be able to view it via an existing sites URL. I want to be able to view the WordPress site via https://www.somedomain.com/blog. I have created a sub folder within the current site files titled ‘blog’. This is now at https://www.somedomain.com/blog. I have dropped the files in. But what do I need to do to make it viewable? For example, do I need to amend the wp-config.php file? It is currently setup as:
DB_NAME – blog, DB_USER – root, DB_PASSWORD – root, DB_HOST – localhost, DB_CHASET – utf8, DB_COLLATE – *blank*

Also does the initial landing page to https://www.somedomain.com/blog need to be an html, for example?

Thanks in advance
Tom