Okay, so you have bought into ONE. ONE works through validation of data by ePoS- their version of Proof of Staking. I'll let you read up on your own about why theirs is innovative and the details. Essentially to make this work, you need delegators and validators to keep everything secure. In this case, you "lock" your coins with a validator by delegating your coins to them- it makes the network work, secures it, and provides the "gas" (poor terminology but trying to make it easy) to keep everything on the chain valid. In return for lending your coins (you always own the key so they are always yours, not theirs) they pay you interest. So for example, I have 500k ONE and in return, they pay me about 400-500 coins a week simply to allow them to use them to validate transactions. They are mine, I can pull them anytime, but in the meantime, I am getting free money/coins. I would be holding them anyway, but now I get interest. Plus, it stabilizes the price because people aren't pulling out and selling on a whim, it takes 2-3 days to unstake. It is win/win.
I suggest you join the r/harmony_one group at Reddit for all the deets.