I followed all the steps precisely and have gone back to check multiple times where I have gone wrong, but couldn't find anything. I am missing a space to enter email in step 98. I added email field to meeting (as in step 78.) Again I'm not sure where I went wrong.

My guess is that when you created the Email field, you clicked through the Next, Next... part quickly and when you do that, the pages you are skipping over don't get a chance to fully load and execute their code which includes making the field available to forms, etc. So go back to Object Manager > Meeting > Fields & Relationships and just delete the Email field and then remake it but this time, click slowly through the Next, Next etc so those pages fully load and do their code. Then that field should show up when you try to add a record.