How to create a form

[eluser]ealonw[/eluser]
Hello all! Im an admin, Linux geek turned coder.. I took to PHP because I work with Mysql on Linux all the time. What Im trying to do is create a simple form in codeigniter that includes: couple input boxes checkboxes and radio button. Can someone give me a good guide on how thats done. I want to write the results to a file and echo a message after the form is complete. I can do this with just PHP scripting but not the codeigniter way. Can anyone help me along. This would be my first time coding using CI and Im really interested in learning.

Functions:
1. Fill out the form
2. Write the results to text file
3. Echo message after form complete

Attached is the HTML form in TEXT version