You are not required to vote for everything on the ballot. Your ballot will not be canceled or disqualified if you leave some races or ballot measures blank.
That said, if you’d like information about what’s going to appear on your ballot, you can use this Sample Ballot Lookup tool. After you type in your address to bring up your sample ballot you can click on the names of the candidates and, in some cases, the ballot measures, to get more information about them.