unfortunately i dont know if or when i would have time to do a tutorial, but on the page i linked it tells you what pages you have to edit and are usually called Newvar and so on.
so any line that has newvar in it, you replace with a name that you want to call the new field.
So, open the files they list, copy in the code they show on the site, change the variables (newvar) to something that references your field, and copy that code to the remaining files in step 3-6.
