The typical schedule for dogs is a series of vaccinations between 7 & 16 weeks, including the 1-yr Rabies, followed by boosters the following year.
Typically, the Rabies given after the first year is a 3-yr vaccination. I have personally not experienced anyone giving a 3-yr Rabies to a puppy, only the 1-yr. So for certain, I would make sure the dog is up to date on the Rabies (required by law in most municipalities).
Additionally, there are vaccinations that are highly recommended & others that are optional.
Recommended: Parvo, Hepatitis, Leptospirosis, Distemper. There is a combo vaccine (DHLPP, includes Parainfluenza) that many vets give as a 3-yr booster. Since you do not know if this dog has ANY vaccinations, I would recommend that one also.
Optional vaccines: Corona virus, Lyme's & Bordetella (kennel cough). I personally do not give these, nor do I recommend them to my puppy owners. There is some evidence that giving Lyme's vaccines may cause a more severe case of Lyme's if the dog contracts it despite the vaccine. Corona & Kennel Cough are rarely life-threatening. Just like the flu for humans, dogs can still get different strains of Kennel Cough, & the vaccination doesn't cover all strains.
Once you have given the vaccines for this year (Rabies & the DHLPP), you can either repeat them every 3 years, or opt to only give the Rabies & do titers for the others. A titer is a blood culture to check for antibody immunty against those diseases; if it is low, then the vaccine is given, if it is high, the dog still has protection. The plus of doing a titer is the dog is not over-vaccinated (which can cause issues in some breeds & with some conditions) but the negative is that if the titer comes back low, the vaccine must be given, at an additional cost.
Check with your local humane society, animal control & pet stores. Often you can find vaccination clinics or low-cost clinics for such things.
T.
I've been a breeder & breed-enthusiast of Rhodesian Ridgebacks since 2000.This is information I give my puppy owners, through my research & recommendations of my personal vets.