You're going to have to find an index.php if you want to get much further
$ sudo find / -name index.php
The file should be in /var/www
Cheers!
pi@raspberrypi ~ $ sudo find / -name index.php
/var/www/install/index.php
/var/www/admin/index.php
/usr/share/phpmyadmin/setup/index.php
/usr/share/phpmyadmin/index.php
pi@raspberrypi ~ $
Update: I tried re-running the install/index.php and got the following:
Validating Entries...Success!
Checking DB connectivity...
Warning: mysqli_connect(): (28000/1045): Access denied for user 'root'@'localhost' (using password: YES) in /var/www/install/includes/configprocessor.php on line 52
Success!
Checking config folder permissions...Success!
Cannot connect the the database using the supplied information.
Please press the back button on your browser to fix these errors
There were no errors I knew of.