Upon arriving to a fire their are many different jobs like the hydrant man which upon arriving to the fire the truck will stop at the closest hydrant possible to the fire and usually the youngest member on the truck will get off and start to wrap the line around the hydrant so its secure and the driver can pull off. This does not mean your the low man on the totem pole because with out you those firemen would not get the water they need to put out the fire.
More jobs may be to stay with your OIC (officer in command) and bring other firefighters tools, lights etc.
Firefighters get many fire calls ranging to ems assists (which is where the fire team is needed to help out medics lift cars of someone or even if all they need is a ladder) All the way to a commercial building fire which may be a condominium on fire with flammable liquids inside.
Being on the job is much more dangerous then you think. for instance its 3 oclock in the morning and your waken up for a call, you make it to the station to find out that theres a storage unit on fire so you gear up and get ready to roll. Upon arriving on scene you notice its a fairly big place and the owner dosent know whats inside and of the units because its not her responsibility so you may not know weather your going into a meth lab or your walking into bottles of gas cans and highly flammable liquids so you always have to prepare for the worst.