Click on the bath/changing table. If you've already given the child its bath then it should be on the table. Make sure it's bottoms are off first then drag the eye to the diaper then change if needed.

Your baby obviously needs to be sick in order to medicate, but anyways you first need to purchase the correct medicine whether your baby is coughing, sneezing etc. Then click on the red medicate sign on the bottom right scroll down menu. Select/click on the correct medicine. It will be the only lit up one. Lastly slide it to your baby in the crib. The baby should feel better after 30 minutes :)