I don't undersand what this mean exactly 14 Days Min/28 Days Max Stake ?
When yours coin are 14 Days in yours wallet they stake and after 28 Days in your wallet they don't Stake ?
No, 14 days until your coins are able to be staked, then they keeping gaining weight against the network until day 28, at which point the coins become at their maximum weight and won't pay any higher for as long as it takes to stake, until they stake and reset the coin age.
For example (not actual values):
day 1 coin = no stake
day 14 = able to stake, network weight 0, payout percent something like (20/365)x1 day's weight(dw)
day 15 = able to stake, if didn't stake before this day: network weight 1, payout percent something like [(20/365)x2dw]x staked coins
day 20 = able to stake, if didn't stake before this day: network weight 6, payout percent something like [(20/365)x6dw]x staked coins
day 28 = able to stake, if didn't stake before this day: network weight 14, payout percent something like [(20/365)x15dw]x staked coins
day 29 = able to stake, if didn't stake before this day: network weight 14, payout percent something like [(20/365)x15dw]x staked coins
day infinity = same as day 29
Once they stake and finish confirms, the coins go back to day 1.
To clarify, network weight figures I used in example are 100% incorrect values, but the principle is the same. There is also the time factor, I'm using whole days, but staking can occur at, say, Hour 25 or 7 or 39.5, etc etc.
This just an example, and I know this not 100% accurate, there are other factors like different bunches of different aged coins, but this is the easiest way to try to explain PoS, imo.
