Girls. The daughter has coughed with phlegm for the first time, runny …

Girls. The daughter has coughed with phlegm for the first time, runny nose. There's no fever. The doctor said to give Anisept and Ambrobene. As far as I know, they usually don't give syrups to children under 3 years old. I can't do massage, tried but it doesn't work. We do inhalation, then she coughs and seems afraid and holds back the cough. How to make the phlegm come out? Only the second day of coughing, yesterday coughed a little before bed. Got infected from her niece. How to help so that he doesn't start coughing?