When is a block actually added onto the blockchain?

My current understanding is as follows:

1. Miner completes PoW process and broadcasts new block & certificate to rest of network.
2. Other nodes verify certificate, their local EVM state changes to include this block, then they propagate to more nodes.
3. After ~12.6 seconds it has reached X? percentage of nodes.
4. At this point the block has been officially chained onto the blockchain?

Where exactly is the point where the block is chained?