Just download WordPress from the Download tab above, extract the files, use FTP to upload the files to your host, then create/edit the wp-config.php to be the same values (including $table_prefix) as you used before.
If you had a backup of your files (as explained in WordPress Backups) you can just upload those.
If you have a bunch of media that was stored in something like wp-content/uploads then you will want to retrieve that from your backup or talk to your hosting company.
Please note, your posts/pages/categories/tags/users/comments are maintained in your database, not the files discussed above.