Business letter

I'm a entreprenuerial management students.As a part of our curriculum we are having our annual Business Planning and Implementation, wherein students are subdivided into groups to which they prefer and make a feasibility study about what business they prefer and implement it for at least 6 months and if the business is going well it can be a good source and be a stable business for us.

me and my partners send in the diff. company about business proposal. and they reply like this"We would appreciate if you can send us a the expected number of students who will be joining and most importantly, your letter should be signed by your school personnel, administration, immediate supervisor and/or professor. We shall await your reply. Thank you!

I don't know how i.m suppose to write. I want to inform them that we are the main or management firm that has a contact people to help and to be part of the project.

July, 3 2014

Dear Madam/Sir,

Thank you for given us an opportunity to be part of your company.
The 000 partnership (tom,lala,mimi) who is the main management firm has a contact people to be our part for doing the project.

something like that.

could you give me some advice or idea on how I.m going to write.
thanks a lot!