I want a horizontal business photo during the day, In the place on the back wall

I want a horizontal business photo during the day, In the place on the back wall there is a horizontal opaque red painting , a la derecha un ventanal que entra luz and to the left hay una pared, and to the left, on the same line as the camera. There will be a flash with a translucent umbrella illuminating the part that is in shadow. You will see 13 people looking at the camera, Half standing and the other half sitting.