Tired the quickfix, here is the output
@bot:/var/www/html/MarginBot-master$ php -f install.php
error_reporting(E_ALL&~E_NOTICE);
PHP Warning: session_start(): Cannot send session cookie - headers already sent by (output started at /var/www/html/MarginBot-master/install.php:1) in /var/www/html/MarginBot-master/inc/config.php on line 4
PHP Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at /var/www/html/MarginBot-master/install.php:1) in /var/www/html/MarginBot-master/inc/config.php on line 4
PHP Notice: Undefined index: doInstall in /var/www/html/MarginBot-master/install.php on line 10
PHP Notice: Undefined index: doInstall in /var/www/html/MarginBot-master/install.php on line 168
You have been trying to run this from a web browser, not just the terminal, right? It is a form you'll need to put information into. Running it from a browser, it should ignore those warnings and notices and show the page without a problem.