It worked! Thank you so much for the detailed instructions. I was unable to add my child though. He has two extra digits in his UCI.Follow below steps only after you have landed. It gives only 5 attempts in one day.
1) Login to CIC account.
2) Go to section "Link an existing application to this account". Click on "Link application to this account" button.
3) Select category as PR Card
4) Select "Unique Client Identifier (UCI) and Family Name"
5) Fill required details (please make sure capital, small, comma etc.)
6) Provide landing date in "Date you became a permanent resident"
7) Click on search my application.
8) after application searched make sure you submit application else not linked.
However, for some people linking becomes impossible. This is primarily because people put their birth city not as per what is written in your passport. Birth city has to match exactly as in Passport including punctuation marks if any.
Once you have successfully linked your application it will shown you as "Submited" status and once it is ready for dispatch it will go into "Approved" status.
If you receive any photo request then it will not change any status. Regularly check PR card processing time on CIC website as photo request or PR card approval both come in last 5-10 days (i.e if processing time is 63 days then after 55 days you will be able to see some movement.)Hope it will work.