Just click the Post button in the top right of the screen when you're looking at each forum and start a new thread for each new topic.
Re. finding doctors. Well there's a thread around somewhere (I'll try and find it) with personally recommended doctors. Usually, you need to see your GP/family doctor and get a referral to a GI doc (gastro-enterologist). Only a GI doc can do all the neccessary tests (colonoscopy etc) that are needed to rule out other GI problems. Your GP also really needs to check you out or refer you elsewhere to rule out the other possible IBS-mimics like gyno probs if you're female.