Use your mouse to move the queens ( =black circles [I'm a minimalistic designer]).
The queens form a solution if they can't capture each other.
A queen can capture another one if it is in the same row, column or diagonal.

Use the stepper to change the board size.

The background becomes green if you found the solution.

I really don't understand the low rating. Please post what you didn't like

(Board background bug fixed)
(Invalid placement bug fixed)