If you're sure you already added the Comments field to your Meeting object, my guess is that when you were creating that field, you clicked too quickly through the Next, Next, etc part. Remember when Max was saying to click slowly through those? That's because you're skipping over pages that need to fully load & execute some code. In this case, that code makes the Comments field visible to all the users in your account. If you clicked Next too quickly, before that happened, then Comments may be there but just not showing up because its visibility is not turned on.
To unhide it, go to Setup > Object Manager, Meeting and then Fields & Relationships and click on Comments (NOT on Edit). Then click Set Field-Level Security (upper center of the page). Then click the checkbox next to the column-header Visible. That will turn on the field’s visibility for all user types listed below, including yours (Admin). Then click Save and when you go back to where you were, it should be showing up and you can enter stuff into it.
If you're sure you already added the Comments field to your Meeting object, my guess is that when you were creating that field, you clicked too quickly through the Next, Next, etc part. Remember when Max was saying to click slowly through those? That's because you're skipping over pages that need to fully load & execute some code. In this case, that code makes the Comments field visible to all the users in your account. If you clicked Next too quickly, before that happened, then Comments may be there but just not showing up because its visibility is not turned on.
To unhide it, go to Setup > Object Manager, Meeting and then Fields & Relationships and click on Comments (NOT on Edit). Then click Set Field-Level Security (upper center of the page). Then click the checkbox next to the column-header Visible. That will turn on the field’s visibility for all user types listed below, including yours (Admin). Then click Save and when you go back to where you were, it should be showing up and you can enter stuff into it.