cisco 2511

i have to make a lease line connection and in my isp i am using cisco 2511. I need to configure the serial 0/0 port of this cisco for my solution. Can anybody tell me what can i do for this . In my cisco i am using ios 11.2, and i have a class c network devided in some subnets. From this class c i have my coustomer a ip for its domain. Please what can i do in this situation?