Adjust the light sources inside a placed light fixture
Open a placed light fixture's own panel to set the position, type, intensity and colour of each of its light sources.
A placed light fixture lists its light sources in its own panel (Lights > Lights > Light 1, Light 2).
Each light source has Position/Shifting X / Y / Z, Light Type (Spot Light | Point Light), Intensity (%) (a 0-100 slider) and Color.
A Spot Light adds Spot Angle (Deg) and Advanced > Penumbra and Direction x / y / z.
A ceiling light (Furnish > Lights > Ceiling Light 1) carries two point lights.