CD Changers are an option so don't be so sure yours should have it. If it does/did, it'll be in the front trunk. If it's missing you'll at least need a MOST loop connector to close the system and it may need reset w/ the Porsche PIWIS system to take it out of the loop.
Contributing members at Renntech.org can download a users manual. In the mean time, here's a link to a fuse panel diagram from Mike Focke's '01S from his google Boxster page (basically same for most 986 Boxsters):
Cut & paste this link:
156972798683730054-a-1802744773732722657-s-sites.googlegroups.com/site/mikefocke2/fuzebox01S.jpg
Good luck
Hybrid Mode
