Marlin - flow chart & acceleration

Hi,
At uni I have a project that include 3D printer. I was wondering if there is any flow chart for Marlin firmware or if someone could tell me where in code I can find accelerations, look ahead and Gcode (just started with this and am slowly getting trough files "motor control, marlin_main, planer and stepper" I am guessing I will find my answers there, but there is a lot of code thats why i would really appreciate any hint thank you).

Cheers,
Ram