How does the bitcoind get current blocks when we start that?
Yes, bitcoin downloads all its blocks off other bitcoin nodes that it connects to, hence the term peer-to-peer (P2P) network. During the initial block download, when a node starts for the first time, it must download all blocks since the beginning of bitcoin (the genesis block), so it must download these from full nodes which store them all, unlike pruned nodes which only store some of the blockchain, not the whole thing.