"How atheist buried when they die?" --> like anybody else; your manner of burial is entirely predicated upon your wishes.
"How they get married?" --> I assume you mean ceremonially, in which case, I would suggest a non-denominational ceremony.
"How do you guys life without fear of the existence of HIM??" --> It's just something that comes naturally to atheists; we shrug off the chains of religious dogmatism and (within the parameters of legality) do whatever we damn well please-- and enjoy much more fulfilling lives as a result.

Fuck gods. You don't need them.