Question about Full nodes and validator nodes ethereum 2.0

Just wanted to ask about something I don’t fully understand. I get that validator will have to run a full node and validators will be the ones forging the new blocks. But does the validator validate all the transactions before the new block has been created. Also when full nodes receive a new block will it have to go through and validate the transactions again itself before storing the block data because surely it has to do this to run transactions with smart contract info and set and change storage values in its own records. I just don’t fully get this process and what it means for validators to ‘validate’ transactions.