That would be because, when you were supposed to add the Contact Name to the Meeting Attendance object, either you skipped the steps or messed them up. Go to Setup > Objects > Meeting Attendance > Fields & Relationships and if Contact Name appears there, delete it. Either way, create it using the steps and follow them carefully so they will work and you will see Contact Name there when you get back to where you were stuck.
That would be because, when you were supposed to add the Contact Name to the Meeting Attendance object, either you skipped the steps or messed them up. Go to Setup > Objects > Meeting Attendance > Fields & Relationships and if Contact Name appears there, delete it. Either way, create it using the steps and follow them carefully so they will work and you will see Contact Name there when you get back to where you were stuck.
Let me know, ok?