To add you rental income, you nee to add the Form T776.

Start by clicking the forms button described in the following screen capture:

 

The next window should be displayed, just search for T776 and double click the first one: T776(1) then click OK.

You should see the form open on your window and you can enter your income as shown in the followinf example.

We have also added some renatl expenses.

Once you are done, you should be able to see your rental income on your T1 general.