I am extremely glad you are researching first, it can be overwhelming at first but it is a VERY rewarding adventure. Bearded Dragons are very loving and cuddly creatures and believe it or not, they actually miss you when you're gone. They are very intelligent and, have a distinct personality. I have had many reptile in my many years on the earth and, dragons are by far the best I have ever had.
A 40gl breeder is an ok size for an adult but it tends to be a bit confining for them, that is why we recommend a 4x2x2 enclosure.
Lights such as UVB and basking are a VERY important part of having a healthy dragon.
For a UVB I highly recommend an Arcadia 12%D3 or a Reptisun 10.0 T5 HO to get anywhere near what a dragon requires for good bone health and, metabolizing it's meals.
Basking bulbs are what provides Heat for proper digestion ....also very important to get the heat gradients they need.
No loose substrates, only solid...I use rough texture tile for flooring (substrate), you can also use, Paper towels, nonadhesive shelf liner or newsprint. Loose substrates can cause impaction when ingested and, harbor bacteria. The solid ones I mentioned can be cleaned easily and, pose no threat to your dragons health.
Temperatures must be well regulated so a Temp gun or a digital heat probe is a must because those stick on thermometers can be off quite a bit.
Night heat is only needed when the temps in your home drop below 65F, if it does you will need a CHE (ceramic heat emitter) to aid in keeping it up. Colored lights should never be used (day or night), they confuse them and, disturb their sleep patterns.
Karrie hit the nail on the head when she warn about advice from Petsmart, Petco and, other big stores being wrong on so many levels. They have killed more dragons after the sale with bad advice than I care to think about. They tell you that Beaded Dragons are a beginner reptile, do not fall for it.
Once you get everything set up correctly YES, they are fairly easy but, the trick is in the setup.
If you have any questions feel free to ask, that is why we are here!!!