Hacked. How do I get back into admin panel

[mmm3]

First, I'm an amateur so I need things explained in simple terms.

My forum was hacked and I can't get into the admin. panel. I'm assuming if I upload a backup file, it will reset it to my password again?

Which file do I re-upload? Is it the config.php file? Do I need to make any changes first?

Thanks!

[Dismounted]

Create a new dummy account, then upload tools.php from the do_not_upload folder. Access tools.php, and make your dummy account an admin. Then login to the Admin CP with the dummy, and change your main account's password.