XF 1.5 How to import my database?

I'm confused sorry, but how do i import my sql database into a brand new installation of 1.5.20 XF? I haven't touched anything on the normal installation.
You would need to do an XF1 import: https://xenforo.com/help/importing/

It's not clear why you're importing into a new installation and not just upgrading the existing one.
My old xenforo 1.5.21 got hacked, I need to reupload the files. How do I do this? I uploaded the xenforo files @ http://fn-accounts.com as you can see i haven't installed it yet. Do I install it, then go to phpmyadmin and then import the database after it's installed?