The CWB is automatically added to your return when you enter working income, and your net income is below the net income level set for your province or territory of residence. However, you may become ineligible for the CWB after adding other information (ex: tuition, more income). If you are seeing a warning regarding the CWB, then you can click on the warning to get an option or Review (or Fix It).

I'm in a similar situation and this answer isn't helpful at all. The only thing that happens when I click "review" is it gives me the option click either "applies to me" or "ignore." It does not give any option to review or fix it and I can't find anywhere to indicate that I do not want to claim the CWB. 

@agdgdgrrbjn Click on "applies to me".