Ssmart contracts

Hey! I'm just starting to learn about the Etherum network and I got some questions.

I learned (correct me if I'm wrong) that Etherum is a decentralized infrastructure (= network of nodes) that host a blockchain service on top of it. Every node on this network stores the complete history of the blockchain from the genesis and must agree on the state of the EVM (which I did not understand that much, but anyway).

Blockchain is composed of blocks, and every block is composed by some transactions and some other data (the hash of the parent I guess(?)). The thing that I'm not understanding is, where are smart contract stored? Are they stored on blocks or somewhere else?