Perfect, thanks.
So Samsung screens have that stupid little joystick button on the back, and that's how you access the screen controls like brightness (and colour and stuff).
The button is described on page 10 of the manual.
Then you definitely don't need to get new test prints. Your job is simply to make your screen match the prints you already have.
But yes, you must make sure your Photoshop Color Settings are on "North America General Purpose 2" the way they should be.