Its adjustable, right now its at 6.12%. You just need to hold it for at least a month it appears and what they do is pay you with monthly "staking awards" with that particular coin. What I also noticed is the staking award, is paid on the purchase price of the coin, for instance if the coin dipped to $3.50 and you bought at that price and staked that coin, you are only going to get an APR on the $3.50, so if the coin rockets to $50 two days later and you continue to hold, no bueno on receiving an APR on the $50.
At least that is how my staking transaction rewards appear,
@Tapxe might have a better understanding?