How to attach a cdr to a forum post?

Trying to resolve a problem, and I've been asked to attach a file of the problem. I can't figure out how. There is an option tab to attach a file somewhere, according to what I've found on the forum, but I can't find it. There's are buttons for Word, Media, Table, Anchor (?), but no file where I can upload my cdr. I'd appreciate a heads up. Thanks..