Unzip Files
1) Unzip all files from "attachmax script" inside a folder.

Upload
2) Upload all of these files into your public_html directory (example /home/yourusername/public_html/*
(In Plesk its usually httpdocs)

------------------------------------------------------------

Alternative Approach for ssh or cpanel users.
1) Upload the zip file into chosen directory
i.e /home/username/public_html

2)Either use Cpanel option to unzip the file or use ssh command "unzip filename.zip"