The minimum limit is 2 members, on the other hand the maximum number of members is 999. Note that the number of free slots must always be lower them the number of members, for example a team with 5 members might have 4 vacancy only.
You can only create one notice at a time (can be edited) which will remain active during 24 hours after created. Once you log out, it will be removed. It will also be deleted 30 minutes after the start time.