I think there may be some misunderstanding here. To my knowledge, Instagram does not offer the feature to make your following list private. Your Instagram profile and posts can be made private, but your followers and following lists are always visible to other users. However, if you really need to hide your following list, you might consider creating a new, private account where you follow only those users you’re comfortable with others knowing about. Just remember, anyone who you allow to follow this account will be able to see your followers and following list.