This lift demands more mobility and strength from your T-spine to press overhead into the proper position. Use it to work your way up to do doing a proper standing overhead press.
As you press, squeeze your glutes and core to maintain your pelvic position. If you lose your pelvic position, the stress will transfer to your lower back.
Finish the lift with both dumbbells directly overhead while maintaining a straight line from the dumbbell to the ground.
It's okay that you don't know how to deadlift if you were never taught properly. But if you still don't know after reading this article, that's a different story.