Heya, backers can head on over to qisoftware.ca to receive their key. What platform did you back on?
Kickstarter:
paypal - If by paypal, you have to use the email connected to said paypal account at the time
card - If by card, you have to create an account with the email attached to kickstarter
Indiegogo:
Here you will have to create an account using the same email as used on Indiegogo
QI's own store:
Log in to your account, head on over to "Orders" and you will see it there.
Let me know if you need any further help!