If you're a non-resident, then in your Statement of World Income, it will ask you for your Net Income amounts from foreign sources. So, you would use taxes you paid on your foreign income to calculate those amounts. 

If you're a resident or became a resident, you can include foreign taxes paid for the time that you were a resident. Use the Foreign slip if the amounts are not included on a Canadian tax slip. You may also be eligible for the Foreign Tax Credit.