Registration tab (and question setting) doesn't show at top of a scheduled meeting page

I have scheduled a meeting, with a specific title. 

I want to add questions which people answer at registration, and to collect their email addresses. 

The guidance says there should be a tab for registration which shows up at the top of the page after I've scheduled the meeting (and ticked the box which says require registration).
Where has it gone to and how can I access it? 

I'm using a pro account.  Note this is for a meeting, not webinar.