One of the most important factors in post ranking on Instagram is Time Spent. This factor points to this issue that how much time users spend on viewing a post. Instagram calculates the extent of importance and attractiveness of a post by examining this factor in followers of a particular page.
If this is higher in a special post by a page in a particular post, Instagram notices the importance of that particular post and displays it to more followers. In the case of more reception, the possibility of that particular post on Explorer page increases and as a result, attractive videos and text posts have more chance for the explorer page.
For increasing this extent, you can produce attractive video content, text or educational posts, or good and useful slides. By doing these actions, you can increase your chance of displaying your posts on Explorer page.