Help: CUDA starter

I am new to CUDA. Can you guys please help me out? I need to perform following task:

  1. Acquire data through GPU from CPU
  2. Do some basic calculation on data
  3. transfer back to CPU and save the file

I know C and C++ but I am just starting in CUDA so please help me out…

You can look at vecadd example in section 3.2.2 of CUDA programming guide.