Make sure the chick is alert and awake. This should stimulate a feeding response. A healthy chick will begin to beg for food. Place the tip if the syringe into the chicks mouth while supporting the chick with your opposite hand. Give only a couple of drops at first until the chick catches on.
Tiny chicks can aspirate very easily.
At this age aspiration is fatal. Watch the chicks chest to see the crop begin to expand. At this age you can clearly see the fluid enter the crop. Day one chicks have very tiny crops , do not try to feed until the crop is bulging. The chick's crop will slowly stretch to accommodate larger feedings as time progresses.