Welcome to the world of chameleons!
Good to see that you are researching keeping a chameleon before you get one!
You need an appropriate cage and cage set up, a method of providing water, lights, supplements, temperature gauges, hoods to keep the lights in, etc.
The cage can be glass with appropriate ventilation or screen. Which you use partly depends on where you live. You need plants (preferably real, well-washed, non-toxic) to provide cover for the chameleon and vines or branches for the chameleon to sit on and climb on.
Water for hatchlings IMHO is best provided by using a hand mister set on fine. Once the chameleon is several months old a dripper can be added. It can be as simple as a container with a tiny hole in the bottom or as complicated as an automatic mister.
Appropriate temperatures play a part in digestion and thus indirectly in nutrient absorption. For hatchlings you will likely want to keep the temperature more even and moderate than for an adult since the small bodies heat, cool and dehydrate more quickly than an adult's body would.
Exposure to UVB from either direct sunlight or a proper UVB light allows the chameleon to produce D3 so that it can use the calcium in its system to make/keep the bones strong and be used in other systems in the chameleon as well. The UVB should not pass through glass or plastic no matter whether its from the sun or the UVB light. The most often recommended UVB light is the long linear fluorescent Repti-sun 5.0 tube light. Some of the compacts, spirals and tube lights have caused health issues, but so far there have been no bad reports against this one.
The basking/heat light can be a regular incandescent household bulb in a domed hood. The wattage should be determined by the temperature you want to create.
Since many of the feeder insects have a poor ratio of calcium to phosphorus in them, its important to dust the insects just before you feed them to the chameleon at most feedings with a phos.-free calcium powder to help make up for it. (I use Rep-cal phosphorus-free calcium).
If you also dust twice a month with a phos.-free calcium/D3 powder it will ensure that your chameleon gets some D3 without overdoing it. It leaves the chameleon to produce the rest of what it needs through its exposure to the UVB light. D3 from supplements can build up in the system but D3 produced from exposure to UVB shouldn't as long as the chameleon can move in and out of it. (I use Rep-cal phos.-free calcium/D3).
Dusting twice a month as well with a vitamin powder that contains a beta carotene (prOformed) source of vitamin A will ensure that the chameleon gets some vitamins without the danger of overdosing the vitamin A. PrEformed sources of vitamin A can build up in the system and may prevent the D3 from doing its job and push the chameleon towards MBD. However, there is controversy as to whether all/any chameleons can convert the beta carotene and so some people give some prEformed vitamin A once in a while. (I use herptivite.)
Gutloading/feeding the insects well helps to provide what the chameleon needs. I gutload crickets, roaches, locusts, superworms, etc. with an assortment of greens (dandelions, kale, collards, endive, escarole, mustard greens, etc.) and veggies (carrots, squash, sweet potato, sweet red pepper, zucchini, etc.)
Calcium, phos., D3 and vitamin A are important players in bone health and other systems in the chameleon (muscles, etc.) and they need to be in balance. When trying to balance them, you need to look at the supplements, what you feed the insects and what you feed the chameleon.
If you get a female chameleon please be aware that in some species, females can reproduce without having been mated and its important for egglaying females once they are sexually mature to have an appropriate place in the cage to dig to show you that they need to lay eggs. If you don't provide them with a place and if you let them see you watching them when they are digging, the chameleon can end up eggbound.
Here are some good sites for you to read...
Hope this helps!