Hello, i have DFGT but friend of mine give me his pedals, does if i contect them to the DFGT i can use them only Gas and Brake, and what i must do to use the Clutch

I do not see that happening unless some heavy modifications are done?
..I do not think DFGT would ever run with G27 pedals. The only pedals that work with DFGT are the DFGT pedals.

Not entirely true, I have Fanatec CSR Elite pedals with my DFGT but those pedals use an own USB interface.

I have never used this myself but saw it posted few times:

There are adapters like this: http://leobodnar.com/products/DFPG25conn/
To use G25/27 pedals as standalone devices, without pluging them into the wheelbase.

Appearently the G25/27 pedals can also be attached to a DFGT if you open it up and reonnect the wires: https://www.youtube.com/watch?v=eAhNhWNNm-8
Does not work for the clutch because the DFGT electronics have no use for it. But the clutch-pedal could be connected by combining it with any other old USB device, like an old gamepad or joystick.
Well, all a bit cobbled together. Happy soldering

You can wire gas and brake up directly. For the clutch to work you need another channel of another game device (take a look in the thread https://www.lfs.net/forum/thread/67189 )