Hello, I have already completed T5008 , and T1135 .. do I need to complete capital gain summary too?

Amounts for capital gains only need to be entered during the T5008 step. The Investment Profile section is typically saved for non-slip-based capital gains amounts. 
The only time you need to file a T1135 form is when the cost value of the fund where the T5008 slips came from is $100,000 CAD or more. 

"If your foreign property produces income, you will have to report the foreign income on the related lines of your tax return.
For example; use the worksheet to report dividends and interest on line 12100 and use schedule 3 to report capital gains or losses."

For more information, please see our TurboTax articles:

The amount of capital gains from my T5008 is doubl... (intuit.ca)

T1135 Tax Form: Foreign Income Verification | 2022 TurboTax® Canada Tips (intuit.ca)

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