Buying live animals online is a big mistake, IMO. Most of these animals die pretty horrible deaths in trasnport, and there are plenty of unscrupulous people out there who will send you anything lying around. I’d suggest trying to find a local pet shop that sells them, or attending a meeting of invertebrate enthusiasts- these people often breed and sell various species.
Scorpions are relatively easy to keep. They do require humidity, which can be something of a challenge. In the wild they live in burrows to stay out of the sun and prevent dehydration. But too humid an environment will promote the growth of mold and fungus. I have an Emperor scorpion in a 30 gallon tank on a sand/potting soil mix substrate. He gets misted once a day in the morning and he’s now about 3 years old and doing very well. Scorpions are also primarily nocturnal, and you absolutely cannot put their tank in direct sunlight, it will kill them very quickly. Hot rocks can also cause overheating, so I use an undertank heating pad. Don’t put them on Astroturf, their claws can catch in the fibres and rip a leg off.
They don’t eat as much as you might think. Mine lives very well on 5 or 6 crickets a month. They need plenty of hiding spots- those little wooden half-tubes are perfect for them. You can also give them some bark chips (no cedar or any other aromatic wood) to burrow in.
Tank cleaning should be done periodically, say a full clean-out maybe once every 3 months. Use a 1/3 bleach solution to wash the tank and replace the substrate. Every day you should remove any half-eaten crickets or excreta, which you can do with a small slotted spoon. Water should be offered in a small, shallow dish and replaced ever day. Do not give the scorpions wet cotton to drink from like some misinformed pet stores do.
Only feed your scorpion crickets, and gut-load the crickets beforehand by feeding them vegetables, fruit, and dry dogfood so that your scorpion gets the proper nutrients.
You really shouldn’t handle your scorpion. Emperors rarely sting, and their venom is rather weak, but they can pinch hard with their huge front claws, and they are very delicate animals because of their size. A fall from more than a few inches can kill them. Only keep one scorpion to a tank, they are cannibals. To clean the cage, use a piece of paper to sort of scoot your scorpion into a smaller holding tank (those plastic ones with the vented lids are ideal for this) while you clean.
Scorpions are for most people extremely boring. They rarely move, save to eat or drink, and they don’t do that very much. They mainly hide, and will only come out when the room is dark. You can set up a black light near the tank to watch your scorpion at night.
They live surprisingly long for inverts. I know someone who has a female that is coming up on 10 years old, although the males don’t live as long. They will shed their exoskeleton periodically- you can’t feed them while they are molting, and you must keep them slightly moister than usual. But if you can remove the exo skeleton after it’s been shed, you can carefully mount it on toothpicks or small pins to make an interesting display and chart your pet’s growth.
Finally, there are many websites out there with information- do some research, talk to pet store people and scorpion keepers before you decide, and make sure you have the resources and responsibilty to care for this animal. Best of luck.