Resulting from (1) removing irrelevant details (details crucial for an implementation, but irrelevant for an initial mental model) and (2) making use of analogies built around already known concepts.
"Complex maths" is never an excuse to not find that explanation.
Disclaimer: I am a pure mathematician.
In Proof of Stake, the network (roughly!) allocates rewards for validating transactions based on the amount of coins you have, i.e., your stake in the network.
In Proof of Space, the network allocates rewards based on you proving that you are really storing the data you were supposed to store. If you fail to produce a proof for some data item the network expected you to have stored, you lose the reward.
More info:
Sort of? But you're usually not really storing data for proof of space. That's a different kind of system.
So it requires the dedication of some hard/rivalrous real resource, storage space, other than either strictly energy/CPU (PoW) or the protocol’s own tokens (PoStake).
See the Chia ‘Green Paper’ for more details.