If you've been invited to vote, you'll receive an email informing you of the upcoming vote- this is what we call a 'Published' vote. The email includes start and end times as well as details relating to any related meeting the vote will occur within.
Once the related meeting has started, the vote will be 'Open' and you will be able to cast your vote. If there is no related meeting, you can simply access the vote from the link in either email or from the voting module itself. Again, this will only be 'Open' based on the time.
Once opened, you will be presented polling options for the respective resolutions. Configuration of polling is unique based on how this was configured; either a poll per resolution or one poll for all resolutions.
Simply click on your chosen polling option and then select 'Cast vote'.
Once your vote is cast, you can not change this. Additionally, you can not vote twice.