FREE NXT/IGNIS

[Xie89]

Hi all, asked this earlier but didn't get a response so here I go again:

I have a question about NXT, I got into it because of the the free 50% IGNIS you get on the 28th of December. It says you get half the amount you have in NXT at the moment of the snapshot. Since I'm a total noob in this new market, and I can't seem to find out, could anybody explain to me:

What is a snapshot?
And how will I know it happened, where do my IGNIS 'appear'?


Thanks