developing a webite for teachers

Actually we r wishing to develop a website which is alike r- networking for teachers. The teachers of highly qualified r allowed to create their profile and upload their study materials, notes, articles and their researches , which can be viewed by the students and those who finds their uploads useful can access it and can download the notes in the form of pdf's and can also share to other social sites like facebook , twitter etc. The teachers can create their group and can discuss with each other of similar fields also video chatting..
We r having some confusion and finding difficulty to make user interface