Here is a basic introduction to the stack and heap, with examples in C: http://gribblelab.org/CBootcamp/7_Memory_Stack_vs_Heap.html

This might help with continuations: https://en.wikipedia.org/wiki/Continuation

Here is a really simple example of simulating a C return using call/cc:

  (display
    (call/cc
      (lambda (return)
        (display "hello ")
        (return "world")
        (display "never reached"))))