Please help with automake tools

Let's say I have several C source and header files in
a directory.  Is it possible to automatically generate
a Makefile to build these?  I'm getting the impression
that you have to at least write your own configure.in
because when I run automake in the directory where these
.c and .h files reside, I get the following error:

    automake: `configure.ac' or `configure.in' is required


Do I need to create a configure.in first?  If so, where
the "auto" part?


-Thanks