[OS X TeX] simple question: where are the tex directories on a mac?

[Balkenborg, Dieter]

Dear Mac experts
I am completely new to the Mac with no knowledge on unix. I am familiar with Dos and windows and must relearn. 
I have successfully installed TexLive and compiled files with it. Now i want to put my own style files into the appropriate directories, but using "finder" I cannot see any /usr/... directories or by searching find any .sty files on the Macintosh HD. The directories seem to be hidden, at least to the novice Mac user, while on a windows installation the text directory is clearly visible. I apologise for the simple question, but i have not been successful for days.
Yours,
Dieter