Hi! First on, great to see you doing research first. I agree with diggerdrake; check that site out. Tegutalk.com is also a good site to look at. It is run by a well known and respected Tegu breeder.
http://agamainternational.com/ formerly owned and operated by the late Bert Langerwerf is another good info source. One thing I have seen first hand is that young tegus are prone to MBD due to how fast they grow. Good UVB is a must or they may start to get tremors.
My experience started with a neglected Colombian tegu who was estimated at five years old. Before I got him he spent at least three years in a 55 gallon fish tank being fed cat food and not being handled. He ended up very food aggressive, very cage possessive and had physical deformities from not having a proper enclosure. It has taken heavy duty leather gloves, time and work and he'll likely never be a cuddle lizard but he can be taken out and allowed to wander the reptile room with us.
My second tegu was a baby Argentinian black and white that was handed to me at a reptile show while talking to someone about rescued snakes. He came with the words, "You sound like you know what you are doing, want another one? It was dropped and it's hind legs don't work. I don't know if that will heal." With the help of a great herp vet, meds, a hearty appetite and time, he has now regained most use of his hind legs. He is fed outside of his house, climbs my arm to come out, enjoys exploring, snuggles in my sweatshirt (foot long tail hangs out), self potty trained (sort of), figured out how to escape his house twice, goes to sleep in the clean laundry, gets well fed and will try to eat pretty much anything if he's hungry. Including rocks. And dirty socks. He had a teen period where he would give me a passing nip to see if I was food before climbing out of his house. I got him over that by wrapping my hand in a towel before picking him up. He's smart, snuggles on his own terms, needs lots of room, enjoys bathtime and can make pretty stinky poo. He is a total omnivore and loves strawberries. I could go on but I feel like I'm making a dating profile. ::laughs::
Good luck to you in the future. Tegus are another great lizard with a huge personality to match.