How you upload your CMS-based site depends on which CMS you're using and whatever provision it includes for uploading.
Generally you can upload many files through FTP to your public_html directory, but some (such as databases) must be handled separately.
This has nothing to do with DirectAdmin on any level.
Is the CMS provided by your hosting company? If so, check with them for information. If not, then check with whoever supplied your CMS.
Jeff