I've talked to a few people and I think I get the basic gist that you talk to a bunch of people in your field, some outside, make friends and then you have a 'network' of people with certain skills you can fall back on when you need it and your own ability in that area is insufficient and vice versa when they need you.
However, practically, for some reason, I just can't fathom it. Or maybe I don't want to. I don't know. Maybe it's my background/upbringing. I haven't thought about it too much. All I know is that it's important and the few people I have asked about it, I couldn't fully understand the concept. Like who do I do it with? Why is it really that important? How do I do it? And is it really worth it if I find the person disagreeable in some way?