Changed website URLS and folder name

Hey guys

I changed the URLS within the settings and the folder name and now I cannot view the website. I keep getting a 404 error when I try to load the website. I’ve added code to functions.php file, had a look at the database but still won’t work. My original idea was rename the original website and then put another wordpress site as the main site. To access the first site then, you’d type in http://www.example.com/example. But my idea has kind of back fired. Does anybody know a fix to this??