HI Ravjot,1. Go to this below listed link
http://www.cic.gc.ca/english/e-services/mycic.asp
2. Click on continue to Gckey
3. If you have already account created, login with your Username and Password otherwise Click on Sign up to go on next page and create your username, password and security questions.
4. After creating my CIC account, click link application to this account.
5. Then select category as Temporary residence and subcategory as Study Permit and extension.
6. Then select Family name, given name and date of birth option.
7. Fill your family name(surname), given name and date of birth as per Passport or Application form.
8. Next in applicant personal info panel fill Passport information only and DO NOT FILL CITY AND COUNTRY OF BIRTH.
9. Enter your course start date given on your offer letter exact same as that.
10. Enter course end date as on offer letter only month and year is given so enter that only don't select the date.
11. Enter your DLI no. same as given on the offer letter.
12. Next search for your application.
13. Your application will be found and can be linked.
Congratulations !!
I do not have surname on my passport. It is just Given Name: Simranjeet Singh. So I am unable to link my application online because I can'l leave it blank and also not working with surname and given name as Simranjeet Singh.