The admin panel of osTicket is located at:
http://yoursupportdomain.com/scp(http://yoursupportdomain.com/scp)
So scp is not a file it's a folder. During installation of osTicket you had to enter an username and password. You need this to login. Inside the admin panel you will find many things, such as the tickets, many options you can alter to customize osTicket etc.