Lighting, Light Fixtures, Ceiling and Exhaust Fans - Standing lights

I just had new siding on the front of my house and they installed these square plates that match the siding so it looks finished where the standing lights were connected, how do I connect the fixtures since the junction boxes are now recessed? Thanks

There are indentations on the back of the plastic square that measure 4" across in a circle. If you find the center point and measure a 2" radius, cut the plastic and remove the center. You will see your junction box behind it. Using the supplied cross brace, install it on the junction box firmly, then run the long screws out to your fixture bell and attach it to them. Your fixture will suck up tight to the siding block and will be fine.