Way up on the upper left of your screencap, you see where it says "Meeting"? You're trying to add this lookup field to the Meeting object but you're actually supposed to be adding it to the Meeting Attendance object that you just created in Steps 68-77.
In other words, you're trying to connect Meeting to itself! I suspect this is why you're not seeing the proper screen components on Step 82.
Exit out of that and use Object Manager to access the Meeting Attendance object and pick up with Step 78. Then it should work.
Way up on the upper left of your screencap, you see where it says "Meeting"? You're trying to add this lookup field to the Meeting object but you're actually supposed to be adding it to the Meeting Attendance object that you just created in Steps 68-77.
In other words, you're trying to connect Meeting to itself! I suspect this is why you're not seeing the proper screen components on Step 82.
Exit out of that and use Object Manager to access the Meeting Attendance object and pick up with Step 78. Then it should work.
Let me know, ok?