a shaking sound in the car when I press clutch and pedal gas

What is your question?

Yesterday, I went to a mechanic to check the car, he told me you need to change the clutch disc and and the clutch disc plate,however the second day, I felt the car is shaking when I give the car first gear pressing clutch and gas pedal. then , I went to the mechanic, he told me you can try two days to give the disc and clutch flexibility to be get accustomed to work together with the flywheel. I don't trust this mechanic, knowing all pieces of change, are new. your help is highly appreciated.