Node *mknode (parameters);

To make a node you need to allocate memory for it, and initialize any values that need to be, for parameters you want to pass it anything that might change between nodes, like X and Y coordinates, but anything that remains the same, like speed, can be hard-coded into the function.

Node *rmnode (Node *);

List *mklist ();

List *insert (List *, Node *, Node *);

List *append (List *, Node *, Node *);

Your append function will work similarly to vim, that is it will append after another node, not necessarily at the end of the list. You will need to pass the function the list you are adding the node to, the node you are appending to, and the node you are appending. Make sure you rework the next pointers, as to not lose any nodes that were already following the location node, ie change newnode → next to be location → next before changing the location's next to be the new node

List *obtain (List *, Node **);

List *clearlist (List *);

List *rmlist (List *);