when I get to "To add the value in the parameter, choose Meta Box field from the range and we can see the Related Courses field that allows us to choose posts which are related to an instructor.", I do not have the relationships button in the meta box field options?
The relationships are working, i.e. I can add items from one post type to another and they appear in the back end as expected. But when I try and add them to a WP Query in a repeater, they don't show up in the meta box fields section as shown in the tutorial.