I have a rough idea of what proof of stake does. However, I'd like the exact implementation (not the code) but a high-level description with hopefully some actual number, e.g. how many pools verify the transactions for each block, how is the consensus achieved, etc. If anyone knows or can send a resource with that information, it would be appreciated.
You might want start by checking out the documentation library. Go here and search on page for "Ouroboros".
Here's a roadmap of 5 main Cardano eras. In my opinion Shelley era brought the most significant changes to the Proof-of-Stake mechanism compared to Byron and Goguen eras. Shelley brought stake delegation and incentives scheme designed to reach equilibrium around stake pools.
In addition to the above, during the Shelley era, the Cardano network became 100 times decentralized than, for example, the Bitcoin network.