Square clock in the middle of my iPhone screen on my iPhone SE how do i get rid of itLarge square clock in the middle of my Home Screen on my iPhone SE

That sound like it may be a clock widget. To remove a widget, see the following from Add, edit, and remove widgets on iPhone - Apple Support

Remove a widget from the Home Screen

1. Touch and hold the widget to open the quick actions menu.
2. Tap Remove Widget (or Remove Stack), then tap Remove.

Does this appear when your SE is on its side and connected to a charger? If so, that is Standby, a feature added to iOS 17:

Use StandBy to view information at a distance while iPhone is charging - Apple Support

If you do not like this features, you can do Settings > Standby and turn it off.