MPC5775K has 4 cores, but one of them is checker core. It works in lockstep mode with e200z4 core which basically means it executes the same instructions as e200z4 core.
So MPC5775K has 3 main cores and each core executes it's own instructions. There are independent code and data for each core. Please look at the following multi-core example:
Your question is too general so my answer is also general. If you have any more specific question about MPC5775K and multi-core projects, please feel free to write me back.