You get assigned by a random number generator to create the next block. If you fail to create it your only penalty is the opportunity cost (i.e., you miss on the reward that you would have gotten for creating one).

So at any given time only one validator is going to create a block. If you create it, it's going to be included in the blockchain. If you don't create it (or you create but due to network problems fail to communicate it), then the blockchain skips a beat and someone else will create the next one.

If you want a user friendly introduction I recommend you Ben Edgington's book (WIP): https://eth2book.info/altair/

Or straight from the source: https://github.com/ethereum/consensus-specs