Best answer by Mathieu
You will need to visit a Koodo retail location to add a new line under your account. You can see nearby locations on this link.
You will need to get the iPhone unlocked for it to work on Koodo and then restore it to factory settings to finish the unlocking procedure. After that you will need to go to the Koodo location you found using the first link to buy a SIM card for 5$ and pick a monthly plan for the new line.