When someone invites you to a meeting, you will receive an email invitation
Either Accept to accept the invite, respond as Tentative if you are unsure if you can attend or not, or Decline if you cannot attend the meeting
If you would like to type a message to the meeting organiser in your response, select edit the response before sending in the drop down list
If you would like to simply send your response without a message, select send the response now from the drop down list
If you would not like the meeting organiser to be notified of you response, select do not send a response from the drop down list
If you accept or tentatively accept, the meeting will then appear in your calendar
If you decline the meeting, it will not be visible in your calendar