1) AOR (Acknowledgement of receipt) - roughly 30-45 days after application is delivered, getting this means your application was complete (no missing boxes, or signatures, or dates etc)
2) Test and Interview Invite
3) Oath Date
In the background, IRCC will run several checks - domestic, international.
Also, non routine cases could get an RQ (residence questionnaire) if the IO is not satisfied that the applicant has met the 3/5 residency requirement.
Also., fingerprint request for some applicants in between stages 1 and 2