So I created a staging website, that is, a copy of mywebsite.com to a subdomain sta.mywebsite.com.
I did this copy via WordPress’ Softaculous ”Create Staging”. A copy of my public_html folder and phpMyAdmin database were created. But after that, I could not access sta.mywebsite.com due to Error establish database connection. I could not figure out what was wrong, so I decided to reinstall WordPress and to only keep my wp-content folder in sta_public_html. I therefore downloaded the latest WordPress. So, through FTP, I replaced everything in my staged sta_public_html folder but the wp-content folder, which I kept. I then installed WordPress throught the wizard that shows up automatically when accessing site for the first time, and got throught to my WordPress Adminpanel for sta.mywebsite.com. But all content, like the Pages and menu is gone. The new WordPress installation does not read my newly copied database (my staging database), where everything is stored. Also, even if I change the password in the new database table wp_users, I can still log in to WordPress Adminpanel for sta.mywebsite.com with the password I created with the WordPress wizard. Funny thing, if I change that WordPress Adminpanel password in my old, original, database I can still log in with the password that was created during the wizard setup. So I do not know what database the new wordpress is reading, nor where the Adminpanel password is stored
The question is, how can I make my new WordPress installation to read my new copied database? I have not hit the limit of the number of databases I can have.