Updates -do you have to install just the latest one ?

Updates -do you have to install just the latest one or do you have to separately install all the previous ones you missed/skipped as well?

Usually they are cumulative updates, containing all previous updates within a particular version. They typically include instructions as to the version the update applies. Also, in the past if you tried to install an update and the requisite version was not resident on your system, the update would not proceed and a message telling you why would pop up.