I need help in Left-4-Dead-2

I need help in Left-4-Dead-2..
I’ve downloaded a non-single playing mode..
How to play the single mode.. ?
Answer #1
(Okay, I can’t help you with that, but what I can tell you is that please be a little more descriptive with the topic name. It’s one of the helpdesk’srules Good luck with the problem )
like “help needed with left-4-dead-2” or something
Please refrain from mini-modding -
#1.2 We'd like to encourage and thank members to use the report button but not add their own criticism.