How do you vote to start an objective?!!!😱

I preface this by apologising a million times over - if the person who kept asking me to vote reads this, I’m so, so sorry!! You were so patient and I was so pathetic by not being able to figure out how to vote!

I’m on ps5 and can’t figure this out! I’ve looked everywhere 😭😱 Does anyone know how to log a vote that has been started already on the ps5?