I have a newbie question, I already did a little research.
But can you, or someone else tell me as simple as possible, how does PoS work?
Since you're a newbie I'll keep it relatively simple. You "stake" by keeping coins in your wallet and your wallet open, otherwise it can't stake. By proving you have a stake in the coin, you get more coins, kind of like interest at a bank because you have given them money for a float, to maintain the bank's integrity. In this case you are helping to maintain the coin's network integrity.
Each coin network has its own parameters for when a coin "matures", or when it is counted as part of a stake and what the corresponding reward is and how often you get said reward.
Hopefully someone else can either extend or correct my layman explanation.