Are you sure you read it? Because everything is there.
Also, I gave you the timeframe on my post. NOI is valid for 6 months.
This is from the OINP guide (page 10)
3.1 Access the OINP e-Filing Portal
You must access the OINP e-Filing Portal directly from the OINP website where you will find further instructions on how to register for, and apply to, the Human Capital Priorities Stream.
Important:
- You must have received a Notification of Interest (NOI) from Ontario through your IRCC online account before you can apply to the OINP under this stream.
- Your NOI is valid for 6 months, which means that you must submit your application to the OINP within 6 months of receiving your NOI from Ontario.
- Once you register a profile for the Human Capital Priorities Stream in the OINP e-Filing Portal, you have 14 calendar days to complete and submit your application to the OINP. After 14 days, your registration will expire and be withdrawn by the OINP.