Step 1: get a child/baby liquid medicine syringe. (CVS gives these away for free just ask the pharmacist)
Step 2: fill it up with up
Step 3: position the dropper over the opening. (if it's too large or small it will work if you continue to press them together)
Step 4: squeeze the air out of the container you want to fill
Press the dropper down. And repeat as necessary.