Erlang - get http request inside module

I'm new to Erlang and web, and I have next question:

How I can receive http request from next html form in Erlang module?

    <form action="/handler.beam">
      First name:<br>
      <input type="text" name="firstname">
      <br>
      Last name:<br>
      <input type="text" name="lastname">
      <br><br>
      <input type="submit" value="Submit">
    </form>