In Mids' (assuming that is what you are using) at the top click Import/Export, then Short Forum Export. Include the data chunk as well as the link in case your link doesn't work.
sorry at the bottom of the coh forums it tells me i cant in the posting rules section
Don't post the file as an attachment.
Hit Import/Export at the top of mids, Short Forum Export.
The build should be posted in the body of the message like normal text, not as an attachment.
I forgot to mention that after you hit the export button, you PASTE it in the forum post by hitting Ctrl+V. I thought that would be common sense after the popup box from Mids' tells you the build is in the clipboard, but I guess not everyone knows what the clipboard is.
I have a build to post here but at the bottom it says you MAY NOT post attachments, any help out there?