trouble with forward

Hi,

im having the hardest time getting my forward to work.

I have an .htacces in my root folder that should forward to url.com/wordpress. and I want to forward from www. and non-www.

The hoster forward doesnt work and the wordpress internal (in the general settings) breaks the page when I change anything.

I found lots of quick tutorials for the htacces but never one that gives the syntax for a forward to the /wordpress and enables both www and non-www at the same time.

any ideas where I can get an extensive documentation about the htacces?

cheers