Experiment with your heat source well before introducing chicks into the brooder so that you will know at what height to place it to get the desired temperature. You've volunteered to be a mother hen and you have to provide all the food, water, warmth, and protection that your chicks will need. It's not too difficult if your schedule will allow you to be consistent. Typically you will need to tend the brooder twice a day providing fresh feed and water, and replacing soiled litter as needed. Under these conditions it probably isn't necessary to feed the chicks medicated feed and they likely will build up an immunity to coccidiosis over time.
Coccidiosis is recognized by extremely loose droppings and, when severe, by blood in the droppings.
Medicated feed is advisable when chicks will be exposed to members of an existing flock, when their numbers are large, or when they may be in close proximity to wild birds. Chickens are subject to a large number of diseases and parasites. Preventing these diseases and rapidly recognizing them when they do occur is the first line of defense. Be sure to provide adequate protection from predators including the family pet. Predators that can threaten your flock will depend on the area you live in.