Anh Hi,
Thanks for your response, but I'm not sure I understand what my next step should be after creating custom fields.
I've gone ahead and created a custom post type, then gone into the previously-created Field Groups definition, and under "Settings" I've set "Post Type" to the newly-created custom post type, "Tracking". I've left "Show for" as "Posts".
Now when I go to "Trackings > Add new" for the new post type, it's allowing me to insert all the fields I defined. But when I click "Publish" and check the post, none of the custom fields retained the values that I entered.
What am I doing wrong?