I am by no means an expert, but I'll tell you what I know...
Breathing treatments - this depends on the trach and whether or not the patient is vent dependent - for example, my sister doesn't require 02, so she gets blow by treatments or a trach mask.
Replacing the trach - again, this depends on the type of trach. There are different kinds: cuffed, uncuffed, one piece disposable with no inner cannula and "permanent" trachs with inner cannulas. My sister has a one piece disposable uncuffed trach, so the whole trach is removed and a new trach put in with a new trach collar. Other patients may just require a new trach collar and cleaning the inner cannula (sterile technique).
To be honest, if you are going into peds, the parents can be a valuable source of the patient's routine and what works best for them, and probably are the best source to learn about trach care from (as long as they do it correctly), because they do it every day in most cases.
Will you be orienting with an experienced nurse?
pictures of several uncuffed trachs and a cuffed trach
(the skinny thing by the trach is the obturator, used to put in the trach and then immediately removed.)
adult trach with inner cannulas