Locations

make a new forum topic
"Post new forum topic" link at the top of the main forum index and each forum

Subject: title for your topic
Forums: which forum you want it to appear in. Only the fora you have permission to post in will appear in the list
Body: your message
File attachments: click on this to open up the box if you want to attach anything

Easy done :) Trickiest thing is remembering to pick a forum if you go through the "You" box or the Post new forum link at the top of the forum, but it will remind you if you forget ;)