There are two options - if you want to use Hunch templates for IE, it has to be created through Hunch. If you are okay with running with default you can populate the remaining fields and send the campaign to FB, in this case, you won’t be able to see the ad preview, since we cannot pull in the IE settings from FB. You need to use Footer when uploading components to your IE and cannot use Header. While creating a collection ad, you need to click on the + sign, you can create an IE from there and all the necessary fields you need to populate are already ‘open’.
Using Header is not supported in Hunch. Instant Experience cannot be updated once it has been created.