The loop doesn not display the latest posts, it just shows the posts the main query has found. On your search page the main query returns search results, and you can change its order (we have plenty of examples for that on our site).
WordPress looks for the parameter s or /search/ in the request URI and decides to do a search query then. That’s what you see as results. You don’t have to do anything more, if you are happy with those results. It happens automatically.