[BetoPho]

You have to follow various steps:

1. Close the board & backup everything.
2. Move all the files from /public_html to /public_html/sub_directory
3. Change the values in 'setting' table:
   • Change the board URL in the database to '(your_domain)/sub_directory' by adjusting the 'bburl' value.
   • Change the Cookie path to '/sub_directory' or '/' by adjusting the 'cookiepath' value. Safest and easiest value is '/', except when you're using some kind of SSO integration with your site in the same domain.
4. Clear all browser cookie, cache and login into AdminCP of new site address.
5. Change Attachment file paths in case you use File System to store attachment (AdminCP -> Attachments -> Attachment Storage Type).
   In case you use Database to store attachments, this step is not needed.
6. Change Avatar/Profile Picture/Signature file path (AdminCP -> Avatars -> Attachment Storage Type).
7. Clear system cache (AdminCP -> Maintenance -> Clear System Cache).
8. Redirect all URL from old domain to new subdirectory (using .htaccess for example).
9. Open the board.