you are asking about how to create server?
first of all there are two type of servers:
listen server (created by getting into New Game) , they are shutdown when you quit game - usually useful for playing with friend.
dedicated servers - that are ran without graphical interface, they are used for 24h / 7days a week work, you can buy such server from game hosting companies.
on your place i would first search for
http://steampowered.com forums and then thinkning about bots.