Did you find the grid settings as per your previous post?
Lights: the elements in the Furnishing library are just 3D objects, so for objects in the furnishing library, a wall light and a chair (for example) have the same properties.
The correct procedure to show "light" is => insert the desired lighting object (furnishing library) => insert the desired light effect (electrical tab).
When you select a light effect, the properties tab show the different settings for this effect => you can adjust the different parameters in order to obtain the desired effects. It is also important to set the elevation of the light effect.
In the image attached you can see a wall light object + a light effect (point light up and down).
Note that the light effects appear when you render the image or by pressing the "Apply" button.