First, you need to be accepted into a university or college in Manitoba. If you plan to study in Manitoba, then you'll need to apply for Canadian Study Permit and if applicable Temporary Resident Visa. If your spouse and children are accompanying you to Canada, then you should submit your applications together as one package to the nearest Canadian High Commission or VFS (visa centers). You may also apply online together with your family at: http://www.cic.gc.ca/english/my_application/apply_online.asp
Note: if your national requires biometric, then even if you submit your application online, you'll still need to do this at the Canadian Visa Centers.
These are the documents you'll need: http://www.cic.gc.ca/english/study/study-how-documents.asp (so you'll need to meet the financial requirement for your wife and kid).
In your case you'll need the following documents:
Application for Study Permit Made Outside of Canada (IMM1294)
Application for Temporary Resident Visa (if you need entry visa to enter Canada)
Family Information Form (IMM5707)
Supporting documents
Letter of acceptance
Marriage License/Certificate
Proof of Means of Financial Support
Passport or travel document
Passport sized photos (35mm *45mm)
Police report
Medical report (if requested)
For family members (your spouse and child):
Application for Visitor Visa (Temporary Resident Visa) Made Outside of Canada (IMM5257)
Application for work permit (if your spouse qualifies and intends to work in Canada, she may apply for open work permit to look for job while in Canada)
Family Information Form (IMM5707)
Supporting documents
Purpose of Travel
Proof of Means of Financial Support
Passport or travel document
Digital Photo
Police report
Medical report (if requested)
If you intend to enrol your kind in school, then the appropriate permit must be obtained.
In a whole, your chances of having your study permit approved and for your family depends on your financial capacity, travel history, wife's occupation, social ties to your country, etc. The visa officer will assess your application based on several factors. No person in this forum can tell you for sure that you'll be approved or what your family chances are. You may also wish to submit paper application because this channel ensures that you've submitted the right application forms and the supporting documents.
This information serves as a guide. Please consult the Canadian visa centers for more information or submit your application at the visa centers or you may solicit the services of legally authorized person to offer you advise on Canada immigration matters.