Here's how you should lay it out:
Date
Name of recipient (This line and the next two should be single-spaced, this program won't allow me to do that.)
Recipient's address
Rest of address
RE: What your letter is about
Dear Name of recipient
Here you start writing your letter. Begin by expressing your interest in the school. Tell them something you like about the school. Everyone likes getting a compliment. Expand on that information a little. Tell them how you heard about the school and some characteristics of the school that make you want to study there. That's your first paragraph.
Your next paragraph should explain that you have some questions. Then, you ask the questions, focus on any details that are of particular concern to you.
In your next paragraph, you should thank the person to whom you are writing for their time and tell them that you appreciate their response to your questions.
Sincerely,
Your Name