Renting portion of my primary residence

Greetings, 

I am renting %40 of my primary residence based on sq footage, could you please let me know how I can enter expenses on TurboTax and how CRA will know I am only renting small portion of my house (%40) so that it will not be considered as a capital gain in that tax year. 

let’s say my property tax is $5k and %40 of it is $2k, but if I enter $2k, CRA does not know that I am only renting small portion of the property… 
your response would be much appreciated.