edit: put in the link for AaP and capitalized here and there - Tarma 9/18/10
It's important to follow HOL's Chain of Command when you have a question, a problem, a comment or a suggestion. However, before you contact anyone, please read the handbook (these pages) thoroughly.
Student/Squib -> Post Graduate -> Prefect -> Head Student -> Professor -> Head Office
It means that if you are a student with a question, you should contact a prefect first and not a professor or the Head Office. You will probably get an answer more quickly if you follow the chain of command, and it makes things easier for everyone.
Professors and other staff members are often busy with other duties, but a prefect's main duty is to answer your questions. PM a prefect or post in the "Ask a Prefect" board on the HOL Forum - their job is to help you! If one of the prefects can't answer your question (which won't happen since they are all wise and all knowing *g*) you can always ask another prefect! One of them will have the answer. Also please ask one prefect at a time - don't bomb all prefects with the same question at the same time.