The first step is having CRS score. If you have the CRS score and meet the other requirements and you have already joined the pool. The key then would be when is the baby born. 1. Before the AOR(submission of application) 2. After AOR(when the application is in process) 3. After COPR (when the application is approved). If it 1. Then you can add the newborn as long as you have their passport/if you don't then just add a letter of explanation later when you get it you can raise a CSE to add their passport. If it is 2 or 3. You will have to inform IRCC and they will send a list of things to be added to he application for newborn. Either way it is straightforward. Only thing is with an additional application your POF will increase.