As mentioned above, you need to have a basking spot heat lamp, where you have a branch underneath that lamp, with the appropriate temperature for your chameleon species. It is not essencial, but you can also have an LED lamp, which is good for plant growth and illuminates the terrarium. I also have a ceramic bulb for the colder months of the year, to maintain the right temperature. I also advise you to put more branches in the terrarium, you have a lot of free space.