[Ipstenu (Mika Epstein)]

Theming is not coding. Well, it’s HTMLing, which isn’t really coding.

See: https://bbpress.org/documentation/themes/

All you have to really do with your new theme is a style.css (in which all you have to do is specify the name of your theme etc) and the header.php (where all you need is to add the header you want). The rest of the files will be pulled from bbPress’ default theme, Kakumei.