Use a meeting's GUID.
The subject of the meeting (Primary).
The type of activity (Picklist).
Description of up to 4,000 characters.
Location
The GUID of the record related to the meeting.
Primary field of the related record. If you set the objectid field, you MUST set this field as well.
Object number of the object the related record belongs to. If you set the objectid field, you MUST set this field as well.
The GUID of the system user who created the record, can also be set manually. Will be used for permissions.
Priority of the meeting (Picklist).
The GUID of the resource used for the meeting.
Date and time the meeting ends.
Date and time the meeting starts.
Status (Picklist)
200