Just in case you did not catch that from the user manual........
The drone has 2 sets of propellers. 2 labelled A, and 2 labelled B.
The "arms" of the drone should also has markings of A and B........... 2 arms marked A, 2 arms marked B.
A props must go to A arms, B props to B arms.
If they are in the wrong arms, they will rotate, but drone won't fly.