Talk to Pediatrician on Lack Of Vitamin D

My daughter is 2. I have been giving her vidaylin and ferosoft since 3 months. But her vitamin D level came low after blood test. Now doctor has prescribed Sunny D drops. But I am not sure of the dose of sunny d. Is it suppose to be given weekly or everyday? And how many ml? There is no proper guidance on the back of medicine. Also, I give ferosoft and vidalyn together. Is it ok to give them together? Or necessary to give them separate?