Where is "settings" on my SE

It's a grey icon with gears in it..

If you cannot find it on your Home Screen, you can swipe down and search for it by typing Settings into the search field.

Or you can go to your App Library and locate it there, pull down to see an alphabetical list, or type in the search field.

If you cannot find the Settings app on your Home Screen(s), then it is located in the App Library. It is probably accidentally removed from the Home Screen, however, still exists in the App Library. The App Library is the last Home Screen on your iPhone when you continue to SWIPE LEFT until you reach it. Once you are in the App Library, then you can search and find the Settings app. Once found, then you can DRAG the app out of there and place it on your favorite spot of the Home Screen.

Axel F.