To add the value 3 to the front of the Node List (we don't have to make any assumptions about the list being big enough!):

we have to

• create a new Node with data value 3:
  Node tmp = new Node(3);

  

• Make tmp.next referene the first node:
  tmp.next = start;
  
  So tmp.next will then reference the Node with value 5 just like start.

  

• Finally, set start to point the Node that tmp references since it is the new first Node
  start = tmp;