Your confirmation code is used to verify the validity of your email address and was sent to the address you used to register on bitFlyer.
If you did not receive the email address, check your Spam and Promotions folders and that you can access the email address used during the registration.
You will be requested to create a password once you verify your email address. If you have already created a password but forgotten it, use the password recovery feature.
*Make sure to use a secure password. bitFlyer also recommends not to use a password used elsewhere with other services