Not all tortoises hibernate so please do not hibernate your tortoise without taking it to a vet to have them identify the type of tortoise you have. Also there are many rules you must follow in assisting your tortoise in hibernation. I would recommend consulting a vet , in the proper way of helping your tortoise to hibernate , but do not hibernate your tortoise until you have had the species properly identified. The best idea is to take to a vet, if your tortoise should hibernate they can help you do it safely. So you wont have any unexpected things happen . Hope this helps.
Tortoises that are bought from a pet center, should be checked out by a vet to make sure they are old enough , big enough and there are many other factors, for safety during hibernation that you might want to consult a vet to assist you in the process. Tortoises not ready for hibernation , can die during hibernation if they are not ready or prepared for it, and if a female is with eggs they can die as well . So with all the problems that can occur I would suggest that you have the tortoise checked out by a vet, to make sure nothing unexpected happens during hibernation and having the vet assist you in preparing the tortoise for hibernation. Hope this helps some.