Move Site from subdomain to main domain

[ Moved to the Fixing WordPress sub-forum. ]

I have a current Joomla site as the main website for my site, but have created a new site on a subdomain for testing (https://www.breathinginchrist.com/v2). I want to now make this my main site. What do I need to do in order to make the wordpress site my main site now?

thanks!