I don't know the details of your case, but I don't think you need to be detailed to that level. For example, if you worked part-time while you were a student in Canada, that period is can be described in a single line as "educational activities/part-time work" . This is what the immigration consultant at my school told me.
However, please note that my background check is still in progress, and my PR has not been approved yet. If you are concerned about this, please be sure to consult a professional. You should be able to find some who will offer free limited advice on single-issue things such as this.