Restoring and securing a WordPress site on EC2 AWS

Hi, my siteassociazionehospes.it has been attacked in the file system, the files have not been touched or damaged, but some have been added which have led the site to be untouchable on the backend side.
What is needed is to have all the permissions to overwrite the new files and then chmod all the correct parameters.
The AWS ec2 instance is on O.S. ubuntu.