The desire to move data and content from [forum board] to XenForo is completely understandable. Also, you should be aware of CMS2CMS - it is an automated migration service! The transition process will be fast and easy! Everything you must do is determine the URLs and establish the connection between both forums - the current board and the new one, and wait approximately 15 minutes.
Start the Free Demo Migration and review a result - you'll be happily surprised.