Find your Backer Number in 3 steps:
Go to www.kickstarter.com & log in your account.
Then click on the menu "Me" on the top right corner.
Then click "Backed projects".
Click the "+" button to see more details about your MIITO pledge.
Your backer number is preceded by the symbol "#".
Copy this backer number (without the # symbol) to paste it in the required field.