What exactly is staking?
A way to generate coins. In proof of work (PoW), new coins are generated by mining (literally, a reward for solving puzzles using a computer or ASIC). In proof of stake (PoS), coin holders are rewarded for holding their coins with a few new 'minted' coins. Think of it as sort of analogous (but not really!) to interest in a savings account. Staking simply means to hold coins in your wallet for the purpose of gaining these rewards.
PIVX was PoW during its first phase, and now uses a combination of masternodes and PoS to add a few extra coins to the supply. The number/block is determined by a formula listed in the OP and whitepapers. Every reward method has its pros and cons; by combining methods, PIVX aims for a happy medium.
And yes, something like DASH. But there are important differences--again, check out the whitepapers in the OP and on the website, or speak with the Devs on Slack.
Can someone provide the link to the staking calculator/estimator? Much appreciated please.
Staking estimator:
http://178.254.23.111/~pub/DN/DN_masternode_payments_stats.htmlMN Projections:
https://docs.google.com/spreadsheets/d/1Dxze2uEbJQGTg1Qvh19lW-SiExrUIVYE7enK8_KEvd4/edit#gid=0PIVX Dashboard:
http://www.presstab.pw/phpexplorer/PIVX/index.php