How Does Proof-of-Activity Specifically Combine PoW and PoS?

PoA begins with the Proof-of-Work phase, where miners compete to find a valid block header, essentially a blank block. Once a PoW miner finds this header, the network switches to the Proof-of-Stake phase.

In the PoS phase, a random group of stakers is chosen to sign the block and add transactions. This process requires both mining effort and staked capital to validate a block.

The PoW part ensures scarcity of block creation.