Why do I get a "404 Not Found" error message when trying to reach the Joget Workflow app center?

I keep getting an HTTP 404 not found message when trying to reach the app center on "http://localhost:8080/jw/". First, I didn't have a MySQL server, but even after I downloaded it, I still get the same message.

I chose to start the MySQL server as a windows service, and I restarted my computer just to make sure it starts. Are there any steps I should do after installing and configuring the MySQL server before I could access the app center? If not, why am I getting a '404 not found' message instead T_T