“Sort the items by the default program setting” is what it means. The Instagram algorithm that determines the order of posts on your feed is based on your interests, your relationships, and recency.
What happens after 10k followers on Instagram?
Once you have 10k followers, Instagram will make it easier for you to get people to your website via Stories with the swipe up to link feature. Swipe up is the only way to get a direct link from your Instagram to your other web properties. And, it’s available in STORIES, if you have 10k followers.