Hi
I have recently done ECA from CU for B.Tech. To my surprise it was a smooth process. You have to get photocopies of all your marklists and your degree certificate (you can send degree certificate separately to WES as well, but this worked for me).
After that you have to submit the application for official transcript with the required amount paid. Its a bit high because for each additional mark list (i had a lot more than you

)there is a charge and then around 1200 or so as postage charges. You can get correct details from the B Tech enquiry.
I would suggest you pay in WES first and get the reference number so that you can put that in the application form along with the correct WES address.
Get the number of someone in the office and keep inquring the progress to be safe. For me it reached Toronto in about 2 weeks or so.
All the best.