Hi and welcome!
Essentially, what you should be aiming for is areas of both brightness, warmth and also cool and shade, so that your chameleon can move around the cage and themoregulate dependent upon how he feels.
My cage has two basking spots at the top, one slightly warmer than the other, and then the cage gradually goes more and more shady the closer that you get to the bottom, as I have two very large live plants in there, so the light "dapples" near the top with near total shade towards the bottom. The temps range from around 90 degrees at the highest basking temp, to just above 70 near the bottom where it is shady.
I can always tell when my cham thinks its bed-time, as he goes two thirds down the cage onto a large branch near the bottom, curls his tail and waits for me to turn his lights off!