Some coding assitance/direction needed

I'm a young student who also happens to be a PHP coder, I want to create a platform to enable my friends and I share Past Question Papers in .pdf format, i know ELGG can handle this easily but there are some issues I dont seem to understand like:

How to show recent files uploaded in my Year, Department, Faculty and School in a Dashboard widget (multi-tagging ?)
Show recent files tagged my courses
in a Dashboard widget i.e Physics
Allow Instructors mail us periodically in case they have a hint for us
Allow Administrator to moderate uploaded Past Questions first, so that we are double-sure of its usefulness

Thanks, any help would be greatly appreciated.