Usually crucial issues such as vaccination should be considered and planned even before the puppy is brought as this helps one to plan this better when the puppy is at home.
I'll elucidate a basic vaccination schedule for your puppy which will give you a better insight
The first shot is given when a puppy is 1 month old. Subsequent boosters to be given after every 15 days till puppy turns 3 month old. Subsequent boosters to be given after 3-4 months till puppy turns 2 year old. Subsequent boosters can be given after 6 months after the puppy has crossed a 2 year old benchmark.
7 IN 1 ( INCLUDES ALL DEADLY CANINE DISEASES, NAMLY Distemper, Parvavirus, Hepatitis, Parainfluenza and Leptospirosis )
The first shot to be given when puppy is 2 months old. The first booster to be given 1 month after the first vaccination and second booster to be given one month after the first booster is given. Annual boosters should follow after the completion of the 2 boosters shot.
ANTI- RABIES ( Protects the puppy from Rabies virus which is easily transmittable from any other animal via direct contact like bite, this virus can then be transmitted to humans. There is no cure for this disease once human gets infected. This is legal mandatory in India considering Rabies like AIDS is an uncurable disease in the World. )
Your Saint Bernard puppies don't require this vaccination untill they are 3 months old. The booster shot should be given 1 month after the first vaccination was given. After this annual vaccination should follow.