how do PoS work?
Once you have held a coin in your wallet for 30 days it is elegable for POS.
You create 0.8% of the value of coins that are staked.
It is based on individual transactions of coins in you wallet, so if you had lots of 5 coins at a time transfer in from mining you will get 0.8% on each of thos 5 coins, so in other words lots of little amounts paid to you.
When you 'mint' some coins based on POS those coins used to mint the inew coins will be held 'in stake' for 25 confirms, meaning you can't spend them during that time.
ALso the way you get hese extra coins in your wallet the stake gets split into two halves and your freshly minted coin added to that half.
I usually wait until I have a few like this and resend them to myself to group them into one large lot so in 30 days time I will get one single large amount instead of several small amounts.
If you have put a password on your wallet you need to unlock it by using the command
walletpassphrase xxxxxxxxxx 99999999999 true
and replace the xxxxs with your password
At the moment POS equates to 10% PA interest on your coins if you keep them in your wallet