I can send you the application form on your email id , pls share the same. You need to send the hard copy of application form , can courier or speed post the same. Along with it you can send an authorization letter though it may not be required now. We did the same. Authorization letter to collect the transcript will be required along with color photocopies which I mentioned earlier.
First date of admission is generally mentioned on the Admit cards provided during admission. If you are applying for transcripts for the Bachelor's degree, the higher secondary marksheet will have an acknowledgement on the backside from the college where the applicant took admission for bachelors, photocopy of which will be required, else someone has to visit the college to get the verification/attestation done.
Having provided mostly all the required information, suggest you to arrange for someone to visit the university with all required details as I mentioned and re-clarify.