When a block is mined, it is broadcasted to the network, the block passes peer to peer in the network.
Suppose there are 4 nodes in the network (A, B, C, D) When a block is received by a node say A, the new block is validated independently by every node on the network. So, the node validates the block and sends it further to its connected peers.
This ensures that only valid blocks are propagated on the network Nodes validates the block by checking it against a long list of criteria that must all be met Then, independent confirmation of the new blocks by each node and get together into a chain