how to connect dvr using c#?

Question

I have read and tried all the post from c# corner as well as from other websites like codeproject,stackoverflow and others but the code is not working. Here only my requirement is i have to connect DVR in which 8 cameras are connected so i have to access that camera using c# so please tell me clearly friends step by step process because there is no resource clearly on the internet.Tell me regarding how many plugins i have to add and what are the software require to download.