HELP! How can I host Co-Op Missions?

[Wolfram-Harms]

Can anybody lead an old horse to the water?
I find and read so many different things, that I get dizzy.

 

I want to host Co-op missions for some friends, but I cannot quite get there.

I need a compact post that explains the WHOLE thing, router setup, BoS setup, port forwarding etc. - and what is Dserver?

Thanks in advance!