buying ableton with student discount

so i'm planning to buy ableton before this schoolyear ends so i can benefit from the discount by still being a student audiotechniques. but how does it actually work? i already have the signed papars that declare that i'm a student audiotechniques, but i don't know how it goes with the payment. do i have to transfer the discounted amount right away, or only after ableton confirmed my order? the contract says "all payments are due immediately upon receipt of invoice and have to be made according to the quotations of the referring invoice for all goods and services ordered". this would mean that they'll confirm before i need to pay, no? i could use some help of someone who has done it already please :))