First you need to get your account number, phone number and account PIN from your old provider. Then you need to go to a TELUS store to activate your new line, with whatever number on it and then request a number port in. We'll then contact your old provider and get your account with them cancelled. And that's pretty much it.
Let me know if you have further questions.
The most important thing is that your line must be active - ie not suspended or in the process of cancellation - for the port to be completed. Once the number is ported, Telus automatically cancels the line with the previous provider.
As for information, the serial number of your current handset should be enough so bring it with you. Your account number will work as well; the more information you bring, the better.
The process of transferring is rather quick, usually within a few minutes for wireless numbers but up to a couple days for landline numbers being ported over. You will be able to call out right away regardless.